Solid bumpers or spring type buffers may be used.

(1) Solid bumpers shall:

(a) Be built of wood or other suitable resilient material;

(b) Have the ability to resist deterioration from weather; and

(c) Have sufficient strength to withstand, without failure, the impact of a descending conveyance carrying its rated load or counterweight while traveling at 115 percent of its rated speed.

(2) Spring type buffers, if used, shall:

(a) Be built with a minimum stroke of 3/4 in. and with a maximum stroke of 1 1/2 in.; and

(b) Not fully compress when struck by the conveyance carrying its rated load or counterweight and traveling at 115 percent of its rated speed.

(3) Inclined private residence conveyances for transporting property are not required to have bumpers and buffers except when obstructions are encountered.