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Subchapter 7. General Industry Safety Orders
Group 6. Power Transmission Equipment, Prime Movers, Machines and Machine Parts
Article 37. Purpose, Definitions and Standards
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§3943. Guard Standards.

(a) If area of shield guard of wire mesh or expanded metal in a frame exceeds 6 square feet, it shall be reinforced.

(b) Trough or "U" guards shall be installed in accordance with the guidelines illustrated in Figures G-5 and G-6.

(c) An enclosure guard shall be installed so that it completely guards the moving parts.

(d) A nip-point belt and pulley guard shall be constructed so that the nip-points are not exposed to accidental contact.

(e) Horizontal overhead belt guard surfaces subject to contact with the belt shall be smooth. The guard width shall be at least 25% wider than the belt being protected. The clearance need not exceed 6 inches on each side.

(f) Guards for horizontal overhead rope and chain drives shall not be less than 6 inches wider than the drive on each side. Where employees pass under overhead rope and chain drives a shallow trough or other effective means of sufficient strength to carry the weight of the broken chain shall be provided.

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


1. Amendment of subsection (e) filed 7-11-72 as procedural and organizational; effective upon filing (Register 72, No. 29).

2. Repealer and new section filed 10-25-74; effective thirtieth day thereafter (Register 74, No. 43).

3. Amendment of subsections (g) and (h) filed 12-19-78; effective thirtieth day thereafter (Register 79, No. 1).

4. Repealer of subsection (f) and relettering of existing subsections filed 2-20-80; effective thirtieth day thereafter (Register 80, No. 8).

5. Amendment filed 10-9-85; effective thirtieth day thereafter (Register 85, No. 44).

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