PERMANENT RULES
LABOR AND INDUSTRIES
Date of Adoption: July 17, 2002.
Purpose: Dipping and coating operations (dip tanks), chapter 296-835 WAC; chapter 296-24 WAC, General safety and health standards; chapter 296-62 WAC, General occupational health standards; and chapter 296-78 WAC, Safety standards for sawmills and woodworking operations.
The Occupational Safety and Health Administration (OSHA), published a Federal Register notice on March 23, 1999, effective April 23, 1999 (64 FR 13897), relating to the rewrite of their existing "dip tank" standard, making the rules more understandable to employers, employees and others who use them. The standard is shorter and performance-oriented, and updates several technical references. We rewrote the dip tank rules using the "Innovations" format incorporating the OSHA updates.
WAC 296-24-405 Dip tanks containing flammable and combustible
liquids.
Requirements relating to dip tanks have been moved to chapter 296-835 WAC.
Repealed this section.
WAC 296-24-40501 Definitions.
Definitions relating to dip tanks have been moved to WAC 296-835-140.
Repealed this section.
WAC 296-24-40503 Ventilation.
Requirements relating to vapor area ventilation have been moved to WAC 296-835-11010.
Requirements relating to ventilation combined with drying have been moved to WAC 296-835-12060.
Repealed this section.
WAC 296-24-40505 Construction of dip tanks.
Requirements relating to the general construction of dip tanks have been moved to WAC 296-835-11005.
Requirements relating to the design of piping connections on drains and overflow lines have been moved to WAC 296-835-12005.
Requirements relating to overflow pipes have been moved to WAC 296-835-12010.
Requirements relating to the bottom of the overflow connection have been moved to WAC 296-835-12010.
Requirements relating to bottom drains have been moved to WAC 296-835-12015.
Requirements relating to salvage tanks have been moved to WAC 296-835-12010.
Requirements relating to automatic extinguishing facilities (except if using a hardening or tempering tank) have been moved to WAC 296-835-12025.
Requirements relating to automatic extinguishing facilities when using a hardening or tempering tank have been moved to WAC 296-835-13005.
Requirements relating to heating dip tank liquids have been moved to WAC 296-835-12055.
Requirements relating to conveyor systems have been moved to WAC 296-835-12065.
Repealed this section.
WAC 296-24-40507 Liquids used in dip tanks, storage and handling.
Requirements relating to liquids used in dip tanks, storage and handling have been moved to WAC 296-835-12035.
Repealed this section.
WAC 296-24-40509 Electrical and other sources of ignition.
Requirements relating to vapor areas as a source of ignition have been moved to WAC 296-835-12040 and 296-835-12045.
Requirements relating to adjacent areas as a source of ignition have been moved to WAC 296-835-12040.
Repealed this section.
WAC 296-24-40511 Operations and maintenance.
Requirements relating to inspection or tests of dip tank facilities have been moved to WAC 296-835-11025.
Requirements relating to warning signs have been moved to WAC 296-835-12040.
Requirements relating to areas in the vicinity of dip tanks being kept clear of combustible stock and debris have been moved to WAC 296-835-12050.
Requirements relating to waste cans have been moved to WAC 296-835-12050.
Repealed this section.
WAC 296-24-40513 Extinguishment.
Requirements relating to extinguishment have been moved to WAC 296-835-12020.
Requirements relating to automatic water spray extinguishing systems have been moved to WAC 296-835-12025.
Requirements relating to automatic foam extinguishing systems have been moved to WAC 296-835-12025.
Requirements relating to automatic carbon dioxide extinguishing systems have been moved to WAC 296-835-12025.
Requirements relating to automatic dry chemical extinguishing systems have been moved to WAC 296-835-12025.
Requirements relating to dip tank covers have been moved to WAC 296-835-12025.
Repealed this section.
WAC 296-24-40515 Special dip tank operations.
Suggested area of the dip tank that should include the area of the sump and any areas on which paint flows have been moved to a note in WAC 296-835-13015.
Exemption of when hardening and tempering tanks do not require an automatic fire extinguishing system has been moved to WAC 296-835-12025.
Requirements relating to automatic extinguishing facilities when using a hardening or tempering tank have been moved to WAC 296-835-13005.
Requirements relating to hardening and tempering tanks have been moved to WAC 296-835-13005.
Requirements relating to electrostatic apparatus have been moved to WAC 296-835-13010.
Requirements relating to flow coating have been moved to WAC 296-835-13015.
Requirements relating to roll coating have been moved to WAC 296-835-13020.
Repeal this section.
WAC 296-62-11021 Open surface tanks.
A note was added to WAC 296-62-11021 stating that requirements relating to dipping and coating operations have been moved and the requirements left in WAC 296-62-11021 only apply to agriculture.
WAC 296-78-71015 Tanks and chemicals.
Corrected references.
WAC 296-835-100 Scope.
Incorporated language from WAC 296-24-405 and 296-62-11021 into this section to explain the scope of this rule and to summarize it.
WAC 296-835-110 General dip tank requirements.
Incorporated general dip tank requirements into WAC 296-835-11005 through 296-835-11045.
WAC 296-835-11005 Construct safe dip tanks.
Requirements from WAC 296-24-40505 relating to constructing safe dip tanks have been moved to this section.
WAC 296-835-11010 Provide proper ventilation for the vapor area.
Requirements from WAC 296-24-40503 and 296-62-11021 relating to vapor area ventilation have been moved to this section.
WAC 296-835-11015 Take additional precautions if you recirculate
ventilation system exhaust air into the workplace.
Requirements from WAC 296-62-11021 relating to taking additional precautions if you recirculate ventilation system exhaust air into the workplace have been moved to this section.
WAC 296-835-11020 Take additional precautions when using an
exhaust hood.
Requirements from WAC 296-62-11021 relating to precautions that need to be taken if the dip tank uses an exhaust hood have been moved to this section.
WAC 296-835-11025 Periodically inspect your dip tanks and
associated equipment and correct any deficiencies.
Requirements from WAC 296-24-40511 and 296-62-11021 relating to inspection or tests of dip tank facilities have been moved to this section.
WAC 296-835-11030 Make sure employees working near dip tanks know
appropriate first-aid procedures.
Requirements from WAC 296-62-11021 relating to first aid have been moved to this section.
WAC 296-835-11035 Prepare dip tanks before cleaning.
Requirements from WAC 296-62-11021 relating to cleaning dip tanks safely have been moved to this section.
WAC 296-835-11040 Safeguard cyanide tanks.
Requirements from WAC 296-62-11021 relating to dip tanks that use cyanide have been moved to this section.
WAC 296-835-11045 Protect employees during welding, burning or
other work using open flames.
Requirements from WAC 296-62-11021 relating to protecting employees during welding, burning or other work using open flames have been moved to this section.
WAC 296-835-11050 Protect employees that use liquids that may
burn, irritate, or otherwise harm the skin.
Incorporated dip tank requirements relating to using liquids that may burn, irritate, or harm the skin into WAC 296-835-13005.
WAC 296-835-120 Additional requirements for dip tanks using
flammable or combustible liquids.
Incorporated dip tank requirements using flammable or combustible liquids into WAC 296-835-12005 through 296-835-12065.
WAC 296-835-12005 Include additional safeguards when constructing
dip tanks.
Requirements from WAC 296-24-40505 relating to the general construction of dip tanks have been moved to this section.
Requirements from WAC 296-24-40505 relating to the design of piping connections on drains and overflow lines have been moved to this section.
WAC 296-835-12010 Provide overflow pipes.
Requirements from WAC 296-24-40505 relating to overflow pipes have been moved to this section.
Requirements from WAC 296-24-40505 relating to the bottom of the overflow connection have been moved to this section.
WAC 296-835-12015 Provide bottom drains.
Requirements from WAC 296-24-40505 relating to bottom drains have been moved to this section.
Requirements from WAC 296-24-40505 relating to salvage tanks have been moved to this section.
WAC 296-835-12020 Provide fire protection in the vapor area.
Requirements from WAC 296-24-40505 relating to automatic extinguishing facilities (except if using a hardening or tempering tank) have been moved to this section.
Added a note referencing the portable fire extinguishment requirements located in WAC 296-800-300.
WAC 296-835-12025 Provide additional fire protection for large
dip tanks.
Requirements from WAC 296-24-40513 relating to automatic water spray extinguishing systems have been moved to this section.
Requirements from WAC 296-24-40513 relating to automatic foam spray extinguishing systems have been moved to this section.
Requirements from WAC 296-24-40513 relating to automatic carbon dioxide extinguishing systems have been moved to this section.
Requirements from WAC 296-24-40513 relating to automatic dry chemical extinguishing systems have been moved to this section.
Add a note referencing various extinguishing system requirements located in WAC 296-24-622, 296-24-623, and 296-24-627.
Requirements from WAC 296-24-40513 relating to dip tank covers have been moved to this section.
WAC 296-835-12035 Prevent static electricity sparks or arcs when
adding liquids to a dip tank.
Requirements from WAC 296-24-40507 relating to liquids used in dip tanks, storage and handling have been moved to this section.
WAC 296-835-12040 Control ignition sources.
Requirements from WAC 296-24-40509 relating to vapor areas as a source of ignition have been moved to this section.
Requirements from WAC 296-24-40509 relating to adjacent areas as a source of ignition have been moved to this section.
Requirements from WAC 296-24-40511 relating to warning signs have been moved to this section.
Added a reference in this section to see WAC 296-835-13010 for requirements relating to electrostatic equipment.
WAC 296-835-12045 Provide safe electrical wiring and equipment
where the liquid can drip or splash.
Requirements from WAC 296-24-40509 relating to vapor areas as a source of ignition have been moved to this section.
WAC 296-835-12050 Keep the area around dip tanks clear of
combustible material and properly dispose of waste.
Requirements from WAC 296-24-40511 relating to areas in the vicinity of dip tanks being kept clear of combustible stock and debris have been moved to this section.
Requirements from WAC 296-24-40511 relating to waste cans have been moved to this section.
WAC 296-835-12055 Make sure heating the liquid in your dip tanks
does not cause a fire.
Requirements from WAC 296-24-40505 relating to heating dip tank liquids have been moved to this section.
WAC 296-835-12060 Make sure a heating system used for drying
objects does not cause a fire.
Requirements from WAC 296-24-40503 relating to ventilation combined with drying have been moved to this section.
WAC 296-835-12065 Make sure conveyor systems are safe.
Requirements from WAC 296-24-40503 relating to vapor area ventilation have been moved to this section.
Requirements from WAC 296-24-40505 relating to conveyor systems have been moved to this section.
WAC 296-835-130 Additional requirements for dip tanks used for
specific processes.
Incorporated dip tank requirements relating to specific processes WAC 296-835-130 through 296-835-13030.
WAC 296-835-13005 Meet specific requirements if you use a
hardening or tempering tank.
Requirements from WAC 296-24-40515 relating to hardening or tempering tanks have been moved to this section.
Requirements from WAC 296-24-40515 relating to automatic extinguishing facilities when using a hardening or tempering tank have been moved to this section.
WAC 296-835-13010 Meet specific requirements if you use
electrostatic equipment.
Requirements from WAC 296-24-40515 relating to electrostatic apparatus have been moved to this section.
WAC 296-835-13015 Meet specific requirements if you use a flow
coating process.
Requirements from WAC 296-24-40515 relating to flow coating have been moved to this section.
Suggested area of the dip tank, from WAC 296-24-40515, that should include the area of the sump and any areas on which paint flows have been moved to this section.
WAC 296-835-13020 Take additional precautions if your roll
coating operation uses a liquid that has a flashpoint below 140°F
(60° C).
Requirements from WAC 296-24-40515 relating to roll coating have been moved to this section.
WAC 296-835-13025 Provide additional safeguards for vapor
degreasing tanks.
Requirements from WAC 296-62-11021 relating to additional safeguards for vapor degreasing machines have been moved to this section.
WAC 296-835-13030 Control liquid spray over an open surface
cleaning or degreasing tank.
Requirements from WAC 296-62-11021 relating to controlling the spray if you spray a liquid in the air over an open surface cleaning or degreasing tank have been moved to this section.
WAC 296-835-140 Definitions.
Insert the following definitions into this section: "ACGIH," "adjacent area," "ANSI," "approved," "autoignition temperature," "combustible liquid," "detearing," dip tank," "flammable liquid," "flashpoint," "lower flammable limit," "vapor area" and "you."
Citation of Existing Rules Affected by this Order: Amending WAC 296-62-11021 Open surface tanks and 296-78-71015 Tanks and chemicals; and repealing WAC 296-24-405 Dip tanks containing flammable and combustible liquids, 296-24-40501 Definitions, 296-24-40503 Ventilation, 296-24-40505 Construction of dip tanks, 296-24-40507 Liquids used in dip tanks, storage and handling, 296-24-40509 Electrical and other sources of ignition, 296-24-40511 Operations and maintenance, 296-24-40513 Extinguishment, and 296-24-40515 Special dip tank operations.
Statutory Authority for Adoption: RCW 49.17.010, [49.17].040, and [49.17].050.
Adopted under notice filed as WSR 02-07-100 on March 20, 2002.
Changes Other than Editing from Proposed to Adopted Version: As a result of written and oral comments received, the following sections are being changed as indicated below:
CHANGES TO THE RULES (Proposed rule versus rule actually adopted):
WAC 296-62-11021 Open surface tanks.
This note now reads:
"Note: The requirements in this section apply only to agriculture. The general industry requirements relating to dipping and coating operations (dip tanks) have been moved to chapter 296-835 WAC."
WAC 296-835-100 Scope.
Deleted the following paragraph: "Other rules that may apply to your workplace.
The WISHA Safety & Health Core Rules, chapter 296-800 WAC, contains the basic requirements that apply to most employers in Washington. It also contains:
- An introduction that lists important information you should know, including a section on building, fire and electrical codes.
- A resource section that includes a complete list of all WISHA rules, and the labor and industries (L&I) offices.
Other WISHA rules may apply to you, depending on the activities and operations of your workplace. Contact your local L&I office if you are uncertain about which WISHA requirements apply to you.
To go online to access the Safety & Health Core Rules:
http://lni.wa.gov/wisha/corerules/default.htm
For a CD or paper copy contact us:
Mail:
Labor and Industries
P.O. Box 44620
Olympia, WA 98504-4620
Telephone: 1-800-4BE-SAFE (1-800-423-7233)"
WAC 296-835-11010 Provide proper ventilation for the vapor area.
Moved the first two bullets below the note for clarity.
Replaced the word "or" with "and" where the two ANSI standards are referenced.
Clarified the language relating to a separate exhaust system. Replaced the words "Chemical reaction" to "Potentially hazardous chemical reaction."
WAC 296-835-11015 Take additional precautions if you recirculate
ventilation system exhaust air into the workplace.
Rewrote this section. It now reads:
"Only recirculate air that contains no substance at a concentration that could pose a health or safety hazard to employees.
Make sure any exhaust system that recirculates air into the workplace:
- Passes the air through a device that removes contaminants
- Sounds an alarm and automatically shuts down the dip tank operation, if the vapor concentration of any substance in the exhaust air exceeds twenty-five percent of its LFL
- Monitors the concentration of vapor from flammable or combustible liquids with approved equipment."
Note:
The LFL concentration in the air must be determined after the air passes through the air-cleaning device and before the air reenters the workspace.
Most substances will pose a health hazard at a concentration far below twenty-five percent of its LFL.
WAC 296-835-11020 Take additional precautions when using an
exhaust hood.
Clarified the language in the first bullet. It now reads:
"Make sure each room with an exhaust hood has a source of outside air that:"
WAC 296-835-11035 Clean dip tanks safely.
Changed the title of this section to, "Prepare dip tanks before cleaning."
Incorporated the language "open any cleanout doors" in the first sub bullet. It now reads, "Drain the contents of the tank and open any cleanout doors."
Added numbers to distinguish between hazards.
WAC 296-835-12020 Provide fire protection in the vapor area.
Moved all the language except subsection (1) and the reference to WAC 296-835-12025.
WAC 296-835-12025 Make sure automatic fire extinguishing systems
are adequate.
Changed the title of this section to, "Provide additional fire protection for large dip tanks."
Incorporated WAC 296-835-12020, 296-835-12025, and 296-835-12030 into this section for clarity. It now reads,
"You must:
Provide at least one automatic fire extinguishing system or an automatic dip tank cover if the tank:
- Holds one hundred fifty gallons or more of liquid
or
- Has four square feet or more of liquid surface area
Make sure automatic fire extinguishing systems or automatic dip tank covers meet the requirements of Table 1.
Exemption:
An automatic fire extinguishing system or an automatic dip tank cover is not required for a hardening or tempering tank that:
Holds less than five hundred gallons
or
Has less than twenty-five square feet of liquid surface
area.
| IF YOU PROVIDE: | THEN YOU MUST: |
| An automatic fire
extinguishing
system
|
Use extinguishing materials
suitable for a fire fueled by the
liquid in the tank Make sure the system protects the: - Tanks - Drain boards - Stock over drain boards |
| A dip tank cover | Make sure the cover is: - Closed by approved automatic devices in the event of fire - Able to be manually activated - Kept closed when the tank is not being used - Made of noncombustible material or metal-clad material with locked metal joints. |
Automatic fire extinguishing systems have specific requirements. See:
- WAC 296-24-622 for automatic dry chemical extinguishing system requirements
- WAC 296-24-623 for automatic carbon dioxide extinguishing system requirements
- WAC 296-24-627 for automatic water spray extinguishing system and automatic foam extinguishing system requirements."
WAC 296-835-12030 Make sure dip tank covers are adequate.
Incorporated this section into WAC 296-835-12025.
WAC 296-835-12035 Prevent static electricity sparks or arcs when
adding liquids to a dip tank.
Replaced the word "the" with "any" in the first bullet.
WAC 296-835-12040 Control ignition sources.
Subsection (3): Replace the word "the" with "any."
Subsection (3): Deleted first bullet.
Subsection (3): Clarified language in the second bullet. It now reads, "Post an easily seen "no smoking" sign near each dip tank."
WAC 296-835-12050 Keep the area around dip tanks clear of
combustible material and properly dispose of waste.
Added numbers to distinguish between hazards.
WAC 296-835-13010 Meet specific requirements if you use
electrostatic equipment.
Added numbers and headings to distinguish between hazards.
Reformatted for clarity.
WAC 296-835-13030 Control the spray if you spray a liquid over an
open surface cleaning or degreasing tank.
Changed the title of this section to, "Control liquid spray over an open surface cleaning or degreasing tank."
Number of Sections Adopted in Order to Comply with Federal Statute: New 0, Amended 0, Repealed 0; Federal Rules or Standards: New 33, Amended 2, Repealed 9; or Recently Enacted State Statutes: New 0, Amended 0, Repealed 0.
Number of Sections Adopted at Request of a Nongovernmental Entity: New 0, Amended 0, Repealed 0.
Number of Sections Adopted on the Agency's Own Initiative: New 33, Amended 2, Repealed 9.
Number of Sections Adopted in Order to Clarify, Streamline, or Reform Agency Procedures: New 33, Amended 2, Repealed 9.
Number of Sections Adopted Using Negotiated Rule Making:
New 0,
Amended 0,
Repealed 0;
Pilot Rule Making:
New 0,
Amended 0,
Repealed 0;
or Other Alternative Rule Making:
New 33,
Amended 2,
Repealed 9.
Effective Date of Rule:
October 1, 2002.
July 17, 2002
Gary Moore
Director
OTS-5468.6
DIPPING AND COATING OPERATIONS (DIP TANKS)
IMPORTANT:
A dip tank is a container holding a liquid other than plain water that is used for dipping or coating. An object may be completely or partially immersed (in a dip tank) or it may be suspended in a vapor coming from the tank.
Exemption: Dip tanks that use a molten material (molten metal, alloy, salt, etc.) are not covered by this chapter.
This chapter applies to:
A dip tank that uses a liquid other than plain water, or the vapor of the liquid, to:
Clean an object
Coat an object
Alter the surface of an object
OR
Change the character of an object.
Draining or drying an object that has been dipped or coated.
Examples of covered dipping and coating operations include, but are not limited to:
Paint dipping
Electroplating
Anodizing
Pickling
Quenching
Tanning
Degreasing
Stripping
Cleaning
Dyeing
Flow coating
Roll coating.
Reference: You have to do a hazard assessment to identify hazards or potential hazards in your workplace and determine if PPE is necessary to protect your employees. See personal protective equipment (PPE), WAC 296-800-160, in the core rules, chapter 296-800 WAC.
[]
Your responsibility:
Safeguard employees working with dip tanks.
You must:
CONSTRUCTION
Construct safe dip tanks
VENTILATION
Provide proper ventilation for the vapor area
Take additional precautions if you recirculate ventilation system exhaust air into the workplace
Take additional precautions when using an exhaust hood
INSPECTION
Periodically inspect your dip tanks and associated equipment and correct any deficiencies
FIRST AID
Make sure employees working near dip tanks know appropriate first aid procedures
CLEANING
Prepare dip tanks before cleaning
CYANIDE
Safeguard cyanide tanks
WELDING
Protect employees during welding, burning or other work using open flames
LIQUIDS HARMFUL TO SKIN
Provide additional protection for employees working near dip tanks that use liquid that may burn, irritate, or otherwise harm the skin
[]
CONSTRUCTIONYou must:
Make sure dip tanks, including any drain boards, are strong enough to support the expected load.
[]
VENTILATIONYou must:
Make sure mechanical ventilation meets the requirements of one or more of the following standards:
NFPA 34-1995, Standard for Dipping and Coating Processes Using Flammable or Combustible Liquids
ACGIH's "Industrial Ventilation: A Manual of Recommended Practice" (22nd ed., 1995)
ANSI Z9.1-1971, Practices for Ventilation and Operation of Open-Surface Tanks and ANSI Z9.2-1979, Fundamentals Governing the Design and Operation of Local Exhaust Systems.
| Note: | Some, or all, of the consensus standards (such as ANSI and NFPA) may have been revised. If you comply with a later version of a consensus standard, you will be considered to have complied with any previous version of the same consensus standard. |
Limit the vapor area to the smallest practical space by using mechanical ventilation.
Keep airborne concentration of any substance below twenty-five percent of its lower flammable limit (LFL).
Make sure mechanical ventilation draws the flow of air into a hood or exhaust duct.
Have a separate exhaust system for each dip tank if the combination of substances being removed could cause a:
Fire
Explosion
OR
Potentially hazardous chemical reaction.
Reference: You need to keep employee exposure within safe levels when the liquid in a dip tank creates an exposure hazard. See Air contaminants, WAC 296-62-075 through 296-62-07515.
| Note: | You may use a tank cover or material that floats on the surface of the liquid to replace or assist ventilation. The method or combination of methods you choose has to maintain the airborne concentration of the hazardous material and the employee's exposure within safe limits. |
[]
You must:
Only recirculate air that contains no substance at a concentration that could pose a health or safety hazard to employees.
Make sure any exhaust system that recirculates air into the workplace:
Passes the air through a device that removes contaminants
Sounds an alarm and automatically shuts down the dip tank operation, if the vapor concentration of any substance in the exhaust air exceeds twenty-five percent of its LFL
Monitors the concentration of vapor from flammable or combustible liquids with approved equipment.
| Note: | The LFL concentration in the air must be determined after the air passes through the air-cleaning device and before the air reenters the workspace. |
| Most substances will pose a health hazard at a concentration far below twenty-five percent of its LFL. |
[]
You must:
Make sure each room with an exhaust hood has a source of outside air that:
Enters the room in a way that will not interfere with the function of the hood
Replaces at least ninety percent of the air taken in through the hood.
[]
INSPECTIONYou must:
Inspect or test your dip tanks and associated equipment periodically, including:
Covers
Overflow pipes
Bottom drains and valves
Electrical wiring, equipment, and grounding connections
Ventilating systems
Fire extinguishing equipment
Inspect the hoods and ductwork of the ventilation system for corrosion and damage and make sure the airflow is adequate:
At least quarterly during operation
Prior to operation after a prolonged shutdown
Promptly fix any deficiencies found.
| Note: | To assist you in tracking your inspections and actions taken from those inspections, you may want to keep a written record. |
| It is recommended that inspections be at least quarterly even if the system is not operating. Depending on the chemicals in use more frequent inspection may be required. |
[]
FIRST AIDYou must:
Make sure your employees know the appropriate first-aid procedures for the hazards of your dipping and coating operations.
| Note: | First-aid procedures are contained in the Material Safety Data Sheet (MSDS) for the chemicals used in the dip tank. |
| First-aid supplies appropriate for the hazards of the dipping or coating operation need to be located near the dip tank to be considered "readily available" as required by WAC 296-800-15020. |
[]
CLEANINGYou must:
(1) Drain the contents of the tank and open any cleanout doors.
(2) Ventilate the tank to clear any accumulated hazardous vapors.
Reference: There may be requirements that apply before an employee enters a dip tank. See Permit-required confined spaces, WAC 296-62-141 and safety procedures, chapter 296-24 WAC, Part A-4.
[]
CYANIDEYou must:
Provide a dike or other safeguard(s) to prevent cyanide from mixing with an acid if a dip tank fails.
| Note: | This would also apply to spills or other means by which cyanide could come in contact with an acid in sufficient quantity to produce a hazardous gas. |
[]
WELDINGYou must:
Make sure the dip tank and the area around it are thoroughly cleaned of solvents and vapors before performing work involving:
Welding
Burning
OR
Open flames
Reference: There are additional requirements for this type of work. See Welding, cutting and brazing, chapter 296-24 WAC, Part I, and Respiratory protection, chapter 296-62 WAC, Part E.
[]
LIQUIDS HARMFUL TO SKINYou must:
(1) Make sure washing facilities, including hot water, are available for every ten employees that work with dip tank liquids.
(2) Satisfy medical requirements:
Make sure an employee with any small skin abrasion, cut, rash, or open sore receives treatment by a properly designated person.
Make sure an employee with a sore, burn, or other skin lesion that needs medical treatment, has a physician's approval before they perform their regular work.
Make sure employees who work with chromic acid receive periodic examinations of their exposed body parts, especially their nostrils.
| Note: | Periodic means on a yearly basis unless otherwise indicated. |
| Any time chromic acid spills onto an employee's skin or their clothing is saturated, a physician should be responsible for evaluating and monitoring the area where chromic acid made contact with the skin. |
(3) Provide lockers or other storage space to prevent contamination of street clothes.
Reference: You have to do a hazard assessment to identify hazards or potential hazards in your workplace and determine if PPE is necessary to protect your employees. See Personal protective equipment (PPE), WAC 296-800-160, in the safety and health core rules, chapter 296-800 WAC.
[]
IMPORTANT:
This section applies to:
Flammable and combustible liquids (flashpoint below 200°F)
Liquids that have a flashpoint of 200°F (93.3°C) or higher if you:
Heat the liquid
Dip a heated object in the tank
Reference: Store flammable and combustible liquids as required by Flammable and combustible liquids, WAC 296-24-330, in the general safety and health standards.
Your responsibility:
Safeguard employees working with dip tanks containing flammable or combustible liquids
You must:
CONSTRUCTION
Include additional safeguards when constructing dip tanks
Provide overflow pipes
Provide bottom drains
FIRE PROTECTION
Provide fire protection in the vapor area
Provide additional fire protection for large dip tanks
ELECTRICAL WIRING AND EQUIPMENT AND SOURCES OF IGNITION
Prevent static electricity sparks or arcs when adding liquids to a dip tank
Control ignition sources in the vapor area and adjacent area
Provide safe wiring and electrical equipment where the liquid can drip or splash
HOUSEKEEPING
Keep the area around dip tanks clear of combustible material and properly dispose of waste
HEATING LIQUID
Make sure heating the liquid in your dip tanks does not cause a fire
HEAT DRYING
Make sure a heating system used for drying objects does not cause a fire
CONVEYORS
Make sure the conveyor system for dip tanks is safe
[]
CONSTRUCTIONYou must:
(1) Make sure the dip tank, drain boards (if provided), and supports, are made of noncombustible material.
(2) Make sure piping connections on drains and overflow pipes allow easy access to the inside of the pipe for inspection and cleaning.
[]
You must:
Provide an overflow pipe on dip tanks that:
Hold more than one hundred fifty gallons of liquid
OR
Have more than ten square feet of liquid surface area
Make sure the overflow pipe is:
Properly trapped
Able to prevent the dip tank from overflowing
Three inches or more (7.6 cm) in diameter
Discharged to a safe location.
| Note: | Discharged to a safe location could be a: |
| Safe location outside the building | |
| OR | |
| Closed, properly vented salvage tank or tanks that can hold more than the dip tank. |
Make sure the bottom of the overflow pipe is at least six inches (15.2 cm) below the top of the tank.
| Note: | The overflow pipe should be large enough to remove water applied to the liquid surface of the dip tank from automatic sprinklers or other sources in the event of fire. Smaller dip tanks should be equipped with overflow pipes, if practical. |
[]
Exemption: A bottom drain is not required if:
The viscosity of the liquid makes it impractical to empty the tank by gravity or pumping
OR
The dip tank has an automatic closing cover that meets the requirements of WAC 296-835-12030.
You must:
Provide a bottom drain on all dip tanks that hold more than five hundred gallons of liquid.
Make sure the bottom drain:
Is properly trapped
Will empty the dip tank during a fire
Has pipes large enough to empty the tank within five minutes
Uses automatic pumps if gravity draining is not practical
Is capable of both manual and automatic operation
Discharges to a safe location.
| Note: | Discharges to a safe location could be a: |
| Safe location outside the building | |
| OR | |
| Closed, properly vented salvage tank or tanks that can hold more than the dip tank. |
Make sure manual operation of the bottom drain is performed from a safe and easily accessible location.
[]
FIRE PROTECTIONYou must:
Provide a manual fire extinguisher near the tank that is suitable for putting out flammable and combustible liquid fires.
[]
You must:
Provide at least one automatic fire extinguishing system or an automatic dip tank cover if the tank:
Holds one hundred fifty gallons or more of liquid
OR
Has four square feet or more of liquid surface area.
Make sure automatic fire extinguishing systems or automatic dip tank covers meet the requirements of Table 1.
Exemption: An automatic fire extinguishing system or an automatic dip tank cover is not required for a hardening or tempering tank that:
Holds less than five hundred gallons
OR
Has less than twenty-five square feet of liquid surface area.
| IF YOU PROVIDE: | THEN YOU MUST: |
| An automatic fire extinguishing system | Use extinguishing
materials suitable for a fire
fueled by the liquid in the
tank Make sure the system protects the: Tanks Drain boards Stock over drain boards. |
| A dip tank cover | Make sure the cover is: Closed by approved automatic devices in the event of fire Able to be manually activated Kept closed when the tank is not being used Made of noncombustible material or metal-clad material with locked metal joints. |
WAC 296-24-622 for automatic dry chemical extinguishing system requirements
WAC 296-24-623 for automatic carbon dioxide extinguishing system requirements
WAC 296-24-627 for automatic water spray extinguishing system and automatic foam extinguishing system requirements.
[]
ELECTRICAL WIRING AND EQUIPMENT AND SOURCES OF IGNITIONYou must:
Make sure any portable container used to add liquid to the tank is:
Electrically bonded to the dip tank
Positively grounded.
[]
You must:
(1) Make sure the vapor areas and adjacent areas do not have any:
Open flames.
Spark producing devices.
Heated surfaces hot enough to ignite vapors.
(2) Use explosion-proof wiring and equipment in the vapor area.
Reference: Electrical wiring and equipment has to meet the requirements of the applicable hazardous (classified) location. See Hazardous (classified) locations, WAC 296-24-95613. Electrostatic equipment has specific electrical requirements. See WAC 296-835-13010.
You must:
(3) Prohibit smoking in any vapor area:
Post an easily seen "NO SMOKING" sign near each dip tank.
[]
You must:
Make sure all electrical wiring and equipment in the vapor area is approved for areas that have:
Deposits of easily ignited residue
Explosive vapor
Exemption: This does not apply to wiring that is:
In rigid conduit, threaded boxes or fittings
Has no taps, splices, or terminal connections.
[]
HOUSEKEEPINGYou must:
(1) Make sure the area surrounding dip tanks is:
Completely free of combustible debris
As free of combustible stock as possible.
(2) Provide approved metal waste cans that are:
Used for immediate disposal of rags and other material contaminated with liquids from dipping or coating operations
Emptied and the contents properly disposed of at the end of each shift.
[]
HEATING LIQUIDYou must:
Keep the temperature of the liquid in the dip tank:
Below the liquid's boiling point
At least 100°F below the liquid's autoignition temperature.
[]
HEAT DRYINGYou must:
Make sure the heating system used in a drying operation that could cause ignition:
Has adequate mechanical ventilation that operates before and during the drying operation
Shuts down automatically if a ventilating fan fails to maintain adequate ventilation
Is installed as required by NFPA 86-1999, Standard for Ovens and Furnaces.
| Note: | Some, or all, of the consensus standards (such as ANSI and NFPA) may have been revised. If you comply with a later version of a consensus standard, you will be considered to have complied with any previous version of the same consensus standard. |
[]
CONVEYORSYou must:
Make sure the conveyor system shuts down automatically if:
The ventilation system fails to maintain adequate ventilation
OR
There is a fire.
[]
Your responsibility: Safeguard employees working with dip tanks used for specific processes
You must:
HARDENING OR TEMPERING
Meet specific requirements if you use a hardening or tempering tank
ELECTROSTATIC EQUIPMENT
Meet specific requirements if you use electrostatic equipment
FLOW COATING
Meet specific requirements if you use flow coating
ROLL COATING
Take additional precautions if your roll coating operation uses a liquid that has a flashpoint below 140°F (60°C)
VAPOR DEGREASING
Provide additional safeguards for vapor degreasing tanks
SPRAY CLEANING OR DEGREASING
Control liquid spray over an open surface cleaning or degreasing tank
[]
HARDENING OR TEMPERINGYou must:
(1) Provide an automatic fire extinguishing system or an automatic dip tank cover for any hardening and tempering tank that uses flammable or combustible liquids and:
Holds five hundred gallons (1893 L) or more of liquid
OR
Has twenty-five square feet (2.37 m2) or more of liquid surface area.
(2) Prevent fires.
Make sure hardening and tempering tanks are:
Not located on or near combustible flooring.
Located as far away as practical from furnaces.
Equipped with noncombustible hoods and vents (or equally effective devices) for venting to the outside.
Treat vent ducts as flues and keep them away from combustible material, particularly roofs.
(3) Make sure air under pressure is not used to:
Fill the tank
OR
Agitate the liquid in the tank.
(4) Equip each tank with an alarm that will sound when the temperature is within 50°F (10°C) of the liquid's flashpoint (alarm set point).
(5) Make sure a limit switch shuts down conveyors supplying work to the tank when the temperature reaches the alarm setpoint, if operationally practical.
(6) Have a circulating cooling system if the temperature of the liquid can exceed the alarm set point.
| Note: | The bottom drain of the tank may be combined with the oil circulating system if the requirements for bottom drains in WAC 296-835-12015 are satisfied. |
[]
ELECTROSTATIC EQUIPMENTELECTRICAL
You must:
(1) Provide safe electrical equipment.
Make sure electrodes in your equipment are:
Substantial
Rigidly supported
Permanently located
Effectively insulated from ground by insulators
Make sure the insulators are:
Nonporous
Noncombustible
Kept clean and dry
Make sure high voltage leads to electrodes are effectively:
Supported on permanent, suitable insulators
Guarded against accidental contact or grounding.
(2) Make sure transformers, powerpacks, control apparatus, and all other electrical parts of the equipment:
Are located outside the vapor area
OR
Meet the requirements of WAC 296-835-12040.
Exemption: High voltage grids and their connections may be located in the vapor area without meeting the requirements of WAC 296-835-12040.
PAINT DETEARING
You must:
(3) Safeguard paint detearing operations.
Use approved electrostatic equipment in paint detearing operations.
(4) Make sure goods being paint deteared are:
Supported on conveyors
Not manually handled.
(5) Keep a minimum safe distance (twice the sparking distance) between goods being paint deteared and the electrodes or conductors of the electrostatic equipment at all times by:
Arranging the conveyors to provide the necessary distance
Supporting the goods to prevent swinging or movement, if necessary
Post a sign that shows the minimum safe distance (twice the sparking distance) near the equipment, where it can be easily seen.
(6) Keep paint detearing operations separate from storage areas and people by using fences, rails or guards that are:
Made of conducting material
Adequately grounded.
(7) Protect paint detearing operations from fire by installing:
Automatic sprinklers
OR
An approved automatic fire extinguishing system.
(8) Collect and remove paint deposits by:
Providing removable drip plates and screens
Cleaning these plates and screens in a safe location.
AUTOMATIC DISCONNECT REQUIREMENT
You must:
(9) Make sure electrostatic equipment has automatic controls that immediately disconnect the power supply to the high-voltage transformer and signal the operator, if:
Ventilating fans or equipment stop or fail for any reason
Conveyors do not work properly
A ground (or imminent ground) occurs anywhere in the high-voltage system
OR
Goods being paint deteared come within twice the sparking distance of the electrodes or conductors of the equipment.
[]
FLOW COATINGYou must:
(1) Make sure all piping is substantial and rigidly supported.
(2) Make sure the paint is supplied by a:
Gravity tank that does not hold more than ten gallons (38 L)
OR
Direct low-pressure pumping system.
(3) Have an approved heat-actuated device that shuts down the pumping system if there is a fire.
| Note: | The area of the sump, and any areas on which paint flows, should be included in the area of dip tank. |
[]
ROLL COATINGIMPORTANT:
This section applies to the processes of roll coating, roll spreading, or roll impregnating that use a liquid having a flashpoint below 140°F (60°C). Material may be passed directly through a tank or over the surface of a roller that revolves partially submerged in the liquid.
You must:
Prevent sparks from static electricity by:
Bonding and grounding all metallic parts (including rotating parts) and installing static collectors
OR
Maintaining a conductive atmosphere (one with a high relative humidity, for example) in the vapor area.
[]
VAPOR DEGREASINGYou must:
(1) Make sure, if the tank has a condenser or a vapor-level thermostat, that it keeps the vapor level at least:
Thirty-six inches (91 cm) below the top of the tank if the width of the tank is seventy-two inches or more
OR
One-half the tank width below the top of the tank if the tank is less than seventy-two inches wide.
(2) Make sure, if you use gas as a fuel to heat the tank liquid, that the combustion chamber is airtight (except for the flue opening) to prevent solvent vapors from entering the air-fuel mixture.
(3) Make sure the exhaust flue:
Is made of corrosion-resistant material
Extends to the outside
Has a draft diverter if mechanical exhaust is used.
(4) Take special precautions to keep solvent vapors from mixing with the combustion air of the heater if chlorinated or fluorinated hydrocarbon solvents (for example, trichloroethylene or freon) are used in the dip tank.
(5) Keep the temperature of the heating element low enough to keep a solvent or mixture from:
Decomposing
OR
Generating excessive vapor.
[]
SPRAY CLEANING OR DEGREASINGYou must:
Control the spray to the greatest extent feasible by:
Enclosing the spraying operation as completely as possible
Using mechanical ventilation to provide enough inward air velocity to prevent the spray from leaving the vapor area.
| Note: | Mechanical baffles may be used to help prevent the discharge of spray. |
[]
Adjacent area: Any area within twenty feet (6.1 m) of a vapor area that is not separated from the vapor area by tight partitions.
ANSI: American National Standards Institute.
Approved: Approved or listed by a nationally recognized testing laboratory. Refer to federal regulation 29 CFR 1910.7, for definition of nationally recognized testing laboratory.
Autoignition temperature: The minimum temperature required to cause self-sustained combustion without any other source of heat.
Combustible liquid: A liquid having a flashpoint of at least 100°F (37.8°C) and below 200°F (93.3°C). Mixtures with at least ninety-nine percent of their components having flashpoints of 200°F (93.3°C) or higher are not considered combustible liquids.
Detearing: A process for removing excess wet coating material from the bottom edge of a dipped or coated object or material by passing it through an electrostatic field.
Dip tank: A container holding a liquid other than plain water that is used for dipping or coating. An object may be immersed (or partially immersed) in a dip tank or it may be suspended in a vapor coming from the tank.
Flammable liquid: Any liquid having a flashpoint below 100°F (37.8°C), except any mixture having components with flashpoints of 100°F (37.8°C) or higher, the total of which make up ninety-nine percent or more of the total volume of the mixture.
Flashpoint: The minimum temperature at which a liquid gives off a vapor in sufficient concentration to ignite when tested by any of the measurement methods described in the definition of flashpoint in the safety and health core rules, WAC 296-800-370.
Lower flammable limit: The lowest concentration of a material that will propagate a flame. The LFL is usually expressed as a percent by volume of the material in air (or other oxidant).
NFPA: National Fire Protection Association.
Vapor area: Any area in the vicinity of dip tanks, their drain boards or associated drying, conveying, or other equipment where the vapor concentration could exceed twenty-five percent of the lower flammable limit (LFL) for the liquid in the tank.
You: Means the employer. See the definition of employer in the safety and health core rules, WAC 296-800-370.
[]
OTS-5505.2
AMENDATORY SECTION(Amending WSR 01-11-038, filed 5/9/01,
effective 9/1/01)
WAC 296-62-11021
Open surface tanks.
| Note: | The requirements in this section apply only to agriculture. The general industry requirements relating to dipping and coating operations (dip tanks) have been moved to chapter 296-835 WAC. |
(a) This section applies to all operations involving the immersion of materials in liquids, or in the vapors of such liquids, for the purpose of cleaning or altering the surface or adding to or imparting a finish thereto or changing the character of the materials, and their subsequent removal from the liquid or vapor, draining, and drying. These operations include washing, electroplating, anodizing, pickling, quenching, dyeing, dipping, tanning, dressing, bleaching, degreasing, alkaline cleaning, stripping, rinsing, digesting, and other similar operations.
(b) Except where specific construction specifications are prescribed in this section, hoods, ducts, elbows, fans, blowers, and all other exhaust system parts, components, and supports thereof shall be so constructed as to meet conditions of service and to facilitate maintenance and shall conform in construction to the specifications contained in American National Standard Fundamentals Governing the Design and Operation of Local Exhaust Systems, Z9.2-1960.
(2) Classification of open-surface tank operations.
(a) Open-surface tank operations shall be classified into 16 classes, numbered A-1 to D-4, inclusive.
(b) Determination of class. Class is determined by two factors, hazard potential designated by a letter from A to D, inclusive, and rate of gas, vapor, or mist evolution designated by a number from 1 to 4, inclusive (for example, B.3).
(c) Hazard potential is an index, on a scale of from A to D, inclusive, of the severity of the hazard associated with the substance contained in the tank because of the toxic, flammable, or explosive nature of the vapor, gas, or mist produced therefrom. The toxic hazard is determined from the concentration, measured in parts by volume of a gas or vapor, per million parts by volume of contaminated air (ppm), or in milligrams of mist per cubic meter of air (mg/m3), below which ill effects are unlikely to occur to the exposed worker. The concentrations shall be those in WAC 296-62-075 through 296-62-07515.
(d) The relative fire or explosion hazard is measured in degrees Fahrenheit in terms of the closed-cup flash point of the substance in the tank. Detailed information on the prevention of fire hazards in dip tanks may be found in Dip Tanks Containing Flammable or Combustible Liquids, NFPA No. 34-1966, National Fire Protection Association. Where the tank contains a mixture of liquids, other than organic solvents, whose effects are additive, the hygienic standard of the most toxic component (for example, the one having the lowest ppm or mg/m3) shall be used, except where such substance constitutes an insignificantly small fraction of the mixture. For mixtures of organic solvents, their combined effect, rather than that of either individually, shall determine the hazard potential. In the absence of information to the contrary, the effects shall be considered as additive. If the sum of the ratios of the airborne concentration of that contaminant exceeds unity, the toxic concentration shall be considered to have been exceeded. (See Note A of (2)(e) of this section.)
(e) Hazard potential shall be determined from Table 16, with the value indicating greater hazard being used. When the hazardous material may be either a vapor with a permissible exposure limit in ppm or a mist with a TLV in mg/m3, the TLV indicating the greater hazard shall be used (for example, A takes precedence over B or C; B over C; C over D).
| Note A: | |||||||
| c1 | + | c2 | + | c3 | +...+ | cN | >1 |
| PEL | PEL | PEL | PEL | ||||
| where: c = Concentration measured at the operation in ppm. |
|||||||
DETERMINATION OF HAZARD POTENTIAL
Toxicity Group |
||||||||||
Hazard potential |
Gas or vapor (ppm) |
Mist (mg/m3) |
Flash point (in degrees F.) |
|||||||
A . . . . . . . . . . . . |
0 |
- |
10 |
0 |
- |
0.1 |
. . . . |
|||
| B . . . . . . . . . . . . | 11 | - | 100 | 0.11 | - | 1.0 | Under 100 | |||
| C . . . . . . . . . . . . | 101 | - | 500 | 1.1 | - | 10 | 100-200 | |||
| D . . . . . . . . . . . . | Over | 500 | Over | 10 | Over 200 | |||||
(i) The temperature of the liquid in the tank in degrees Fahrenheit;
(ii) The number of degrees Fahrenheit that this temperature is below the boiling point of the liquid in degrees Fahrenheit;
(iii) The relative evaporation of the liquid in still air at room temperature in an arbitrary scale -- fast, medium, slow, or nil; and
(iv) The extent that the tank gases or produces mist in an arbitrary scale -- high, medium, low, and nil. (See Table 17, Note 2.) Gassing depends upon electrochemical or mechanical processes, the effects of which have to be individually evaluated for each installation (see Table 17, Note 3).
(g) Rate of evolution shall be determined from Table 17. When evaporation and gassing yield different rates, the lowest numerical value shall be used.
| TABLE 17 DETERMINATION OF RATE OF GAS, VAPOR, OR MIST EVOLUTION1 |
||||
| Rate | Liquid
tempera- ture, °F |
Degrees below boiling point |
Evaporation2 |
Relative Gassing3 |
1 . . . . . . . . . . . . |
Over 200 |
0-20 |
Fast . . . . . . |
High |
| 2 . . . . . . . . . . . . | 150-200 | 21-50 | Medium . . . | Medium |
| 3 . . . . . . . . . . . . | 94-149 | 51-100 | Slow . . . . . | Low |
| 4 . . . . . . . . . . . . | Under 94 | Over 100 | Nil . . . . . . . | Nil |
| Note 1. | In certain classes of equipment, specifically vapor degreasers, an internal condenser or vapor level thermostat is used to prevent the vapor from leaving the tank during normal operations. In such cases, rate of vapor evolution from the tank into the workroom is not dependent upon the factors listed in the table, but rather upon abnormalities of operating procedure, such as carry out of vapors from excessively fast action, dragout of liquid by entrainment in parts, contamination of solvent by water and other materials, or improper heat balance. When operating procedure is excellent, effective rate of evolution may be taken as 4. When operating procedures are average, the effective rate of evolution may be taken as 3. When operation is poor, a rate of 2 or 1 is indicated, depending upon observed conditions. |
| Note 2. | Relative evaporation rate is determined according to the methods described by A. K. Doolittle in Industrial and Engineering Chemistry, vol. 27, p. 1169, (3) where time for 100 -- percent evaporation is as follows: Fast: 0-3 hours; Medium: 3-12 hours; Slow: 12-50 hours; Nil: more than 50 hours. |
| Note 3. | Gassing means the formation by chemical or electrochemical action of minute bubbles of gas under the surface of the liquid in the tank and is generally limited to aqueous solutions. |
(4) Control requirements.
(a) Control velocities shall conform to Table 18 in all cases where the flow of air past the breathing or working zone of the operator and into the hoods is undisturbed by local environmental conditions, such as open windows, wall fans, unit heaters, or moving machinery.
(b) All tanks exhausted by means of hoods which;
(i) Project over the entire tank;
(ii) Are fixed in position in such a location that the head of the workman, in all his normal operating positions while working at the tank, is in front of all hood openings; and
(iii) Are completely enclosed on at least two sides, shall be considered to be exhausted through an enclosing hood.
(iv) The quantity of air in cubic feet per minute necessary to be exhausted through an enclosing hood shall be not less than the product of the control velocity times the net area of all openings in the enclosure through which air can flow into the hood.
Class (See Sub- paragraph (2) and Tables 16 and 17) |
Enclosing hood (See Subparagraph (4)(ii)) |
Lateral exhaust1 (See Subparagraph (4)(iii)) |
Canopy hood2 (See Sub- paragraph (4)(iv)) |
||||
| One open side |
Two open sides |
Three open sides |
Four open
sides |
||||
A-1 and A-2 |
100 |
150 |
150 |
Do not use |
Do not use |
||
| A-3 (Note 2), |
|||||||
| B-1, B-2, and C-1 |
75 |
100 |
100 |
125 |
175 |
||
| B-3, C-2, and D-1 (Note 3) |
65 |
90 |
75 |
100 |
150 |
||
| A-4 (Note 2), C-3, and D-2 (Note 3) |
50 |
75 |
50 |
75 |
125 |
||
| B-4, C-4, D-3 (Note 3), and D-4 |
|||||||
| General room ventilation required. |
|||||||
| 1 | See Table 19 for computation of ventilation rate. |
| 2 | Do not use canopy hood for Hazard Potential A processes. |
| 3 | Where complete control of hot water is desired, design as next highest class. |
(i) For lateral exhaust hoods over 42 inches wide, or where it is desirable to reduce the amount of air removed from the workroom, air supply slots or orifices shall be provided along the side or the center of the tank opposite from the exhaust slots. The design of such systems shall meet the following criteria:
(A) The supply air volume plus the entrained air shall not exceed 50 percent of the exhaust volume.
(B) The velocity of the supply airstream as it reaches the effective control area of the exhaust slot shall be less than the effective velocity over the exhaust slot area.
(C) The vertical height of the receiving exhaust hood, including any baffle, shall not be less than one-quarter the width of the tank.
(D) The supply airstream shall not be allowed to impinge on obstructions between it and the exhaust slot in such a manner as to significantly interfere with the performance of the exhaust hood.
Required minimum control velocity, f.p.m. (from Table |
|||||||||||
| C.f.m. per sq. ft. to maintain required
minimum velocities at following
ratios (tank width (W)/tank length
(L)).1 3 |
|||||||||||
| 0.0- 0.09 |
0.1- 0.24 |
0.25- 0.49 |
0.5- 0.99 |
1.0- 2.0 |
|||||||
| Hood along one side or two parallel sides of tank when one hood is against
a wall or baffle.2 Also for a manifold along tank centerline.3 |
|||||||||||
| 50 . . . . . . . . . . . . | 50 | 60 | 75 | 90 | 100 | ||||||
| 75 . . . . . . . . . . . . | 75 | 90 | 110 | 130 | 150 | ||||||
| 100 . . . . . . . . . . . . | 100 | 125 | 150 | 175 | 200 | ||||||
| 150 . . . . . . . . . . . . | 150 | 190 | 225 | 260 | 300 | ||||||
| Hood along one side or two parallel sides of free standing tank not against wall or baffle. | |||||||||||
| 50 . . . . . . . . . . . . | 75 | 90 | 100 | 110 | 125 | ||||||
| 75 . . . . . . . . . . . . | 110 | 130 | 150 | 170 | 190 | ||||||
| 100 . . . . . . . . . . . . | 150 | 175 | 200 | 225 | 250 | ||||||
| 150 . . . . . . . . . . . . | 225 | 260 | 300 | 340 | 375 |
||||||
| 1 | It is not practicable to ventilate across the long dimension of a tank whose ratio W/L exceeds 2.0. |
| It is understandable to do so when W/L exceeds 1.0. For circular tanks with lateral exhaust along up the circumference use W/L = 1.0 for over one-half the circumference use W/L = 0.5. |
| 2 | Baffle is a vertical plate the same length as the tank, and with the top of the plate as high as the tank is wide. If the exhaust hood is on the side of a tank against a building wall or close to it, it is perfectly baffled. |
| 3 | Use W/L as tank width in computing when manifold is along centerline, or when hoods are used on two parallel sides of a tank. |
| Tank Width (W) means the effective width over which the hood must pull air to operate (for example, where the hood face is not back from the edge of the tank, this set back must be added in measuring tank width). The surface area of tanks can frequently be reduced and better control obtained (particularly on conveyorized systems) by using covers extending from the upper edges of the slots toward the center of the tank. |
(d) All tanks exhausted by means of hoods which project over the entire tank, and which do not conform to the definition of enclosing hoods, shall be considered to be overhead canopy hoods. The quantity of air in cubic feet per minute necessary to be exhausted through a canopy hood shall be not less than the product of the control velocity times the net area of all openings between the bottom edges of the hood and the top edges of the tank.
(e) The rate of vapor evolution (including steam or products of combustion) from the process shall be estimated. If the rate of vapor evolution is equal to or greater than 10 percent of the calculated exhaust volume required, the exhaust volume shall be increased in equal amount.
(5) Spray cleaning and degreasing. Wherever spraying or other mechanical means are used to disperse a liquid above an open-surface tank, control must be provided for the airborne spray. Such operations shall be enclosed as completely as possible. The inward air velocity into the enclosure shall be sufficient to prevent the discharge of spray into the workroom. Mechanical baffles may be used to help prevent the discharge of spray. Spray painting operations are covered in WAC 296-62-11019.
(6) Control means other than ventilation. Tank covers, foams, beads, chips, or other materials floating on the tank surface so as to confine gases, mists, or vapors to the area under the cover or to the foam, bead, or chip layer; or surface tension depressive agents added to the liquid in the tank to minimize mist formation, or any combination thereof, may all be used as gas, mist, or vapor control means for open-surface tank operations, provided that they effectively reduce the concentrations of hazardous materials in the vicinity of the worker below the limits set in accordance with (2) of this section.
(7) System design.
(a) The equipment for exhausting air shall have sufficient capacity to produce the flow of air required in each of the hoods and openings of the system.
(b) The capacity required in (7)(a) of this section shall be obtained when the airflow producing equipment is operating against the following pressure losses, the sum of which is the static pressure:
(i) Entrance losses into the hood.
(ii) Resistance to airflow in branch pipe including bends and transformations.
(iii) Entrance loss into the main pipe.
(iv) Resistance to airflow in main pipe including bends and transformations.
(v) Resistance of mechanical equipment; that is, filters, washers, condensers, absorbers, etc., plus their entrance and exit losses.
(vi) Resistance in outlet duct and discharge stack.
(c) Two or more operations shall not be connected to the same exhaust system where either one or the combination of the substances removed may constitute a fire, explosion, or chemical reaction hazard in the duct system. Traps or other devices shall be provided to insure that condensate in ducts does not drain back into any tank.
(d) The exhaust system, consisting of hoods, ducts, air mover, and discharge outlet shall be designed in accordance with American National Standard Fundamentals Governing the Design and Operation of Local Exhaust Systems, Z9.2-1960, or the manual, Industrial Ventilation, published by the American Conference of Governmental Industrial Hygienists. Airflow and pressure loss data provided by the manufacturer of any air cleaning device shall be included in the design calculations.
(8) Operation.
(a) The required airflow shall be maintained at all times during which gas, mist, or vapor is emitted from the tank, and at all times the tank, the draining, or the drying area is in operation or use. When the system is first installed, the airflow from each hood shall be measured by means of a pitot traverse in the exhaust duct and corrective action taken if the flow is less than that required. When the proper flow is obtained, the hood static pressure shall be measured and recorded. At intervals of not more than 3 months operation, or after a prolonged shutdown period, the hoods and duct system shall be inspected for evidence of corrosion or damage. In any case where the airflow is found to be less than required, it shall be increased to the required value. (Information on airflow and static pressure measurement and calculations may be found in American National Standard Fundamentals Governing the Design and Operation of Local Exhaust Systems, Z9.2-1960, or in the manual, Industrial Ventilation, published by the American Conference of Governmental Industrial Hygienists.)
(b) The exhaust system shall discharge to the outer air in such a manner that the possibility of its effluent entering any building is at a minimum. Recirculation shall only be through a device for contaminant removal which will prevent the creation of a health hazard in the room or area to which the air is recirculated.
(c) A volume of outside air in the range of 90 percent to 110 percent of the exhaust volume shall be provided to each room having exhaust hoods. The outside air supply shall enter the workroom in such a manner as not to be detrimental to any exhaust hood. The airflow of the makeup air system shall be measured on installation. Periodically, thereafter, the airflow should be remeasured, and corrective action shall be taken when the airflow is below that required. The makeup air shall be uncontaminated.
(9) Personal protection.
(a) All employees working in and around open surface tank operations must be instructed as to the hazards of their respective jobs, and in the personal protection and first aid procedures applicable to these hazards.
(b) All persons required to work in such a manner that their feet may become wet shall be provided with rubber or other impervious boots or shoes, rubbers, or wooden-soled shoes sufficient to keep feet dry.
(c) All persons required to handle work wet with a liquid other than water shall be provided with gloves impervious to such a liquid and of a length sufficient to prevent entrance of liquid into the tops of the gloves. The interior of gloves shall be kept free from corrosive or irritating contaminants.
(d) All persons required to work in such a manner that their clothing may become wet shall be provided with such aprons, coats, jackets, sleeves, or other garments made of rubber, or of other materials impervious to liquids other than water, as are required to keep their clothing dry. Aprons shall extend well below the top of boots to prevent liquid splashing into the boots. Provision of dry, clean, cotton clothing along with rubber shoes or short boots and an apron impervious to liquids other than water shall be considered a satisfactory substitute where small parts are cleaned, plated, or acid dipped in open tanks and rapid work is required.
(e) Whenever there is a danger of splashing, for example,
when additions are made manually to the tanks, or when acids and
chemicals are removed from the tanks, the employees so engaged
shall be required to wear either tight-fitting chemical goggles
or an effective face shield. (((See WAC 296-800-160.))) (See
chapter 296-307 WAC, Part H, Personal protective equipment.)
(f) When, during emergencies as described in (11)(e) of this section, employees must be in areas where concentrations of air contaminants are greater than the limit set by (2)(c) of this section or oxygen concentrations are less than 19.5%, they must be required to wear respirators adequate to reduce their exposure to a level below these limits or that provide adequate oxygen. Such respirators must also be provided in marked, quickly accessible storage compartments built for the purpose, when there exists the possibility of accidental release of hazardous concentrations of air contaminants. Respirators must be certified by NIOSH under 42 CFR part 84 and used in accordance with the applicable provisions of chapter 296-62 WAC Part E.
(g) Near each tank containing a liquid which may burn, irritate, or otherwise be harmful to the skin if splashed upon the worker's body, there shall be a supply of clean cold water. The water pipe (carrying a pressure not exceeding 25 pounds) shall be provided with a quick opening valve and at least 48 inches of hose not smaller than three-fourths inch, so that no time may be lost in washing off liquids from the skin or clothing. Alternatively, deluge showers and eye flushes shall be provided in cases where harmful chemicals may be splashed on parts of the body.
(h) Operators with sores, burns, or other skin lesions requiring medical treatment shall not be allowed to work at their regular operations until so authorized by a physician. Any small skin abrasions, cuts, rash, or open sores which are found or reported shall be treated by a properly designated person so that chance of exposures to the chemicals are removed. Workers exposed to chromic acids shall have a periodic examination made of the nostrils and other parts of the body, to detect incipient ulceration.
(i) Sufficient washing facilities, including soap,
individual towels, and hot water, shall be provided for all
persons required to use or handle any liquids which may burn,
irritate, or otherwise be harmful to the skin, on the basis of at
least one basin (or its equivalent) with a hot water faucet for
every 10 employees. (((See WAC 296-800-230.))) (See chapter 296-307 WAC, Safety standards for agriculture.)
(j) Locker space or equivalent clothing storage facilities shall be provided to prevent contamination of street clothing.
(k) First aid facilities specific to the hazards of the operations conducted shall be readily available.
(10) Special precautions for cyanide. Dikes or other arrangements shall be provided to prevent the possibility of intermixing of cyanide and acid in the event of tank rupture.
(11) Inspection, maintenance, and installation.
(a) Floors and platforms around tanks shall be prevented from becoming slippery both by original type of construction and by frequent flushing. They shall be firm, sound, and of the design and construction to minimize the possibility of tripping.
(b) Before cleaning the interior of any tank, the contents shall be drained off, and the cleanout doors shall be opened where provided. All pockets in tanks or pits, where it is possible for hazardous vapors to collect, shall be ventilated and cleared of such vapors.
(c) Tanks which have been drained to permit employees to enter for the purposes of cleaning, inspection, or maintenance may contain atmospheres which are hazardous to life or health, through the presence of flammable or toxic air contaminants, or through the absence of sufficient oxygen. Before employees shall be permitted to enter any such tank, appropriate tests of the atmosphere shall be made to determine if the limits set by (2)(c) of this section are exceeded, or if the oxygen concentration is less than 19.5%.
(d) If the tests made in accordance with (11)(c) of this section indicate that the atmosphere in the tank is unsafe, before any employee is permitted to enter the tank, the tank shall be ventilated until the hazardous atmosphere is removed, and ventilation shall be continued so as to prevent the occurrence of a hazardous atmosphere as long as an employee is in the tank.
(e) If, in emergencies, such as rescue work, it is necessary to enter a tank which may contain a hazardous atmosphere, suitable respirators, such as self-contained breathing apparatus; hose mask with blower, if there is a possibility of oxygen deficiency; or a gas mask, selected and operated in accordance with (9)(f) of this section, shall be used. If a contaminant in the tank can cause dermatitis, or be absorbed through the skin, the employee entering the tank shall also wear protective clothing. At least one trained standby employee, with suitable respirator, shall be present in the nearest uncontaminated area. The standby employee must be able to communicate with the employee in the tank and be well able to haul him out of the tank with a lifeline if necessary.
(f) Maintenance work requiring welding or open flame, where toxic metal fumes such as cadmium, chromium, or lead may be evolved, shall be done only with sufficient local exhaust ventilation to prevent the creation of a health hazard, or be done with respirators selected and used in accordance with (9)(f) of this section. Welding, or the use of open flames near any solvent cleaning equipment shall be permitted only after such equipment has first been thoroughly cleared of solvents and vapors.
(12) Vapor degreasing tanks.
(a) In any vapor degreasing tank equipped with a condenser and vapor level thermostat, the condenser or thermostat shall keep the level of vapors below the top edge of the tank by a distance at least equal to one-half the tank width, or at least 36 inches, whichever is shorter.
(b) Where gas is used as a fuel for heating vapor degreasing tanks, the combustion chamber shall be of tight construction, except for such openings as the exhaust flue, and those that are necessary for supplying air for combustion. Flues shall be of corrosion-resistant construction and shall extend to the outer air. If mechanical exhaust is used on this flue, a draft diverter shall be used. Special precautions must be taken to prevent solvent fumes from entering the combustion air of this or any other heater when chlorinated or fluorinated hydrocarbon solvents (for example, trichloroethylene; Freon) are used.
(c) Heating elements shall be so designed and maintained that their surface temperature will not cause the solvent or mixture to decompose, break down, or be converted into an excessive quantity of vapor.
(d) Tanks or machines of more than 4 square feet of vapor area, used for solvent cleaning or vapor degreasing, shall be equipped with suitable cleanout or sludge doors located near the bottom of each tank or still. These doors shall be so designed and gasketed that there will be no leakage of solvent when they are closed.
(13) Scope.
(a) This paragraph applies to all operations involving the immersion of materials in liquids, or in the vapors of such liquids, for the purpose of cleaning or altering their surfaces, or adding or imparting a finish thereto, or changing the character of the materials, and their subsequent removal from the liquids or vapors, draining, and drying. Such operations include washing, electroplating, anodizing, pickling, quenching, dyeing, dipping, tanning, dressing, bleaching, degreasing, alkaline cleaning, stripping, rinsing, digesting, and other similar operations, but do not include molten materials handling operations, or surface coating operations.
(b) "Molten materials handling operations" means all operations, other than welding, burning, and soldering operations, involving the use, melting, smelting, or pouring of metals, alloys, salts, or other similar substances in the molten state. Such operations also include heat treating baths, descaling baths, die casting stereotyping, galvanizing, tinning, and similar operations.
(c) "Surface coating operations" means all operations involving the application of protective, decorative, adhesive, or strengthening coating or impregnation to one or more surfaces, or into the interstices of any object or material, by means of spraying, spreading, flowing, brushing, roll coating, pouring, cementing, or similar means; and any subsequent draining or drying operations, excluding open-tank operations.
[Statutory Authority: RCW 49.17.010, [49.17].040, and [49.17].050. 01-11-038, § 296-62-11021, filed 5/9/01, effective 9/1/01; 99-10-071, § 296-62-11021, filed 5/4/99, effective 9/1/99. Statutory Authority: Chapter 49.17 RCW. 91-24-017 (Order 91-07), § 296-62-11021, filed 11/22/91, effective 12/24/91. RCW 49.17.040, 49.17.050, and 49.17.240. 81-16-015 (Order 81-20), § 296-62-11021, filed 7/27/81; 80-11-010 (Order 80-14), § 296-62-11021, filed 8/8/80; Order 73-3, § 296-62-11021, filed 5/7/73.]
OTS-5506.1
AMENDATORY SECTION(Amending WSR 01-11-038, filed 5/9/01,
effective 9/1/01)
WAC 296-78-71015
Tanks and chemicals.
(1) All open vats
and tanks into which workers may fall shall be guarded with
standard railings or screen guards in all cases where such
guarding is possible with regard to practical operation.
(2) Foundations of elevated tanks shall be accessible for inspections. When the tank platform is more than five feet above the ground a stairway or ladder shall be permanently attached.
(3) Every open tank over five feet in height shall be equipped with fixed standard ladders both inside and out, extending from the bottom to the rim of the tank arranged to be accessible to each other, so far as local conditions permit.
(4) The use of chemicals for treating of lumber for
prevention of sap stain or mold or as preservatives, shall
conform to the requirements of ((WAC 296-62-11021, open surface
tanks)) chapter 296-835 WAC, Dipping and coating operations (dip
tanks).
(a) Storage, handling, and use of chemicals. Threshold
limits. Employees shall not be exposed to airborne concentration
of toxic dusts, vapors, mists or gases that exceed the threshold
limit values set forth in chapter ((296-24)) 296-62 WAC, Part
((A-2, general safety and health standards)) H, and chapter 296-62 WAC, Part E, general occupational health standards.
(b) Protective equipment. The use of chemicals shall be
controlled so as to protect employees from harmful exposure to
toxic materials. Where necessary, employees shall be provided
with and required to wear such protective equipment as will
afford adequate protection against harmful exposure as required
by ((chapter 296-24 WAC, Part A-2, general safety and health
standards)) WAC 296-800-160, and chapter 296-62 WAC, Part E,
general occupational health standards.
(5)(a) Means shall be provided and used to collect any excess of chemicals used in treating lumber so as to protect workers from accidental contact with harmful concentrations of toxic chemicals or fumes.
(b) Dip tanks containing flammable or combustible liquids
shall be constructed, maintained and used in accordance with
((WAC 296-24-405 of the general safety and health standards))
chapter 296-835 WAC, Dipping and coating operations (dip tanks).
(c) An evacuation plan shall be developed and implemented for all employees working in the vicinity of dip tanks using flammable and/or combustible liquids. A copy of the plan shall be available at the establishment for inspection at all times. Every employee shall be made aware of the evacuation plan and know what to do in the event of an emergency and be evacuated in accordance with the plan. The plan shall be reviewed with employees at least quarterly and documented.
(d) When automatic foam, automatic carbon dioxide or automatic dry chemical extinguishing systems are used, an alarm device shall be activated to alert employees in the dip tank area before and during the activation of the system. The following combinations of extinguishment systems when used in conjunction with the evacuation plan as stated above will be acceptable in lieu of bottom drains:
(i) A dip tank cover with an automatic foam extinguishing system under the cover, or an automatic carbon dioxide system, or an automatic dry chemical extinguishing system, or an automatic water spray extinguishing system;
(ii) An automatic dry chemical extinguishing system with an automatic carbon dioxide system or a second automatic dry chemical extinguishing system or an automatic foam extinguishing system;
(iii) An automatic carbon dioxide system with a second automatic carbon dioxide system or an automatic foam extinguishing system.
(e) The automatic water spray extinguishing systems,
automatic foam extinguishing systems, and dip tank covers shall
conform with the requirements of ((WAC 296-24-405)) chapter 296-835 WAC, Dipping and coating operations (dip tanks). The
automatic carbon dioxide systems and dry chemical extinguishing
system shall conform with the requirements of WAC 296-24-615 and
296-24-620.
(6) Where workers are engaged in the treating of lumber with chemicals or are required to handle lumber or other materials so treated, the workers shall be provided with, at no cost to the worker, and required to use such protective equipment as will provide complete protection against contact with toxic chemicals or fumes therefrom.
(7) Sanitation requirements. The requirements of WAC 296-800-220 and 296-800-230 (safety and health core rules), shall govern sanitation practices.
(8) The sides of steam vats and soaking pits unless otherwise guarded shall extend forty-two inches above the floor level. The floor adjacent thereto shall be of nonslip construction.
(9) Large steam vats or soaking pits, divided into sections, shall be provided with substantial walkways between each section, each walkway to be provided with standard railings which may be removable if necessary.
(10) Covers shall be removed only from that portion of the steaming vats on which workers are working and a portable railing shall be placed at this point to protect the operators.
(11) Workers shall not ride or step on logs in steam vats.
[Statutory Authority: RCW 49.17.010, [49.17].040, and [49.17].050. 01-11-038, § 296-78-71015, filed 5/9/01, effective 9/1/01. Statutory Authority: Chapter 49.17 RCW. 96-17-056, § 296-78-71015, filed 8/20/96, effective 10/15/96; 94-20-057 (Order 94-16), § 296-78-71015, filed 9/30/94, effective 11/20/94. Statutory Authority: RCW 49.17.040, 49.17.050 and 49.17.240. 81-18-029 (Order 81-21), § 296-78-71015, filed 8/27/81.]
OTS-5481.1
REPEALER
The following sections of the Washington Administrative Code are repealed:
| WAC 296-24-405 | Dip tanks containing flammable or combustible liquids. |
| WAC 296-24-40501 | Definitions. |
| WAC 296-24-40503 | Ventilation. |
| WAC 296-24-40505 | Construction of dip tanks. |
| WAC 296-24-40507 | Liquids used in dip tanks, storage and handling. |
| WAC 296-24-40509 | Electrical and other sources of ignition. |
| WAC 296-24-40511 | Operations and maintenance. |
| WAC 296-24-40513 | Extinguishment. |
| WAC 296-24-40515 | Special dip tank applications. |