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Subchapter 14. Petroleum Safety Orders--Drilling and Production
Article 28. Ladders and Ladderway Openings for Derricks and Masts
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§6599. Ladders for Derricks and Masts.

(a) Except as provided for gin pole masts in Section 6600, every derrick or mast shall be equipped with a fixed ladder or ladders arranged to provide access from the ground, floor level, or a base landing on the vehicle on which it is mounted, to the crown platform and to any intervening fixed platform in or on the derrick or mast.

(b) The width of ladders shall be at least twelve inches (12"), measured from the inside of the side rails except that ladders for telescoping type derricks or masts shall be not less than eleven inches (11").

(c) Rung or step spacing shall be uniform and parallel, and shall be at least twelve inches (12") but not more than sixteen inches (16") from top to top of consecutive rungs or steps. The clear space above the rungs or steps shall be at least six inches (6").

(d) Where sections of ladders are spliced, they shall be supported at the splice so the ladder will be aligned and the splice will not reduce the strength of the ladder.

(e) On the climbing side of the ladder a clear and unobstructed space shall be maintained of at least twelve inches (12") from each side of a line drawn vertically through the ladder width, and of at least twenty-four inches (24") outward, but this does not forbid the use of a safety device to prevent or control falls from a ladder when the use of the device is approved by the Division or designed and constructed in compliance with recognized national standards such as ANSI, UL, or Factory Mutual. This subsection does not apply to ladderway openings in platforms.

(f) Throughout the length and width of the back of the ladder, a space of at least four inches (4") shall be maintained clear of all obstructions that present a tripping hazard, prevent adequate footing, or prevent a secure handhold to the ladder.

(g) No ladder shall lean backward from the vertical.

No ladder shall lean sideways more than five and three-fourths degrees (5 3/4o) from the vertical, provided, however, that ladders for the cantilever type derricks or masts shall not lean sideways more than three degrees (3o).

Ladders shall be so constructed that the rungs or steps are approximately horizontal at the normal operating position of the derrick or mast and never more than two degrees (2o) from the horizontal.

(h) The lowest rung or step of the ladder or ladder section shall be not more than eighteen inches (18") above the ground, floor, or platform landing.

(i) Ladders shall be constructed and secured to the derrick or mast to support all expected working loads.

(j) The top end of each terminating ladder or ladder section providing access to any fixed platform in or on a derrick or mast shall extend at least three and one-half feet (3 1/2') above the platform unless suitable handholds are provided.

(k) Unless a ladder climbing assist device is used, continuous ladders or ladder sections below the racking platform of the derrick or mast shall be provided with platforms at intervals not exceeding forty feet (40') upon which employees may rest.

Such platforms shall be not less than twelve inches (12") in depth nor less than eighteen inches (18") in width. handholds shall be provided above the rest platform. Toeboards and railings are not required.

(l) If ladders are offset, such offsets shall be located at ladder offset rest platforms only.

(m) Ladder cages are not required on any derrick or mast except as provided for in Section 6600 (b) of this article and Section 6589 (a) of Article 25.

(n) Counterweighted ladder climbing assist devices may be used in conjunction with a ladder climbing safety device or in conjunction with rest platforms on the ladder in conformance with these orders. If the assist device is used in conjunction with ladders with rest platforms, the counterweight shall weigh no more than 100 pounds. Employees using the assist device shall be instructed in the proper use of the device, which shall require the use of both hands and feet in contact with the ladder as if climbing with no assist device.

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Amendment filed 7-20-59; effective thirtieth day thereafter (Register 59, No. 12).

2. Amendment of article 28 heading, section heading, section and Note filed 5-8-95; operative 6-7-95 (Register 95, No. 19).

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