Control lines for CDZs

Under 1926.760(c)(3) a Controlled Decking Zone (CDZ) is an area where access is limited while leading edge and initial securement of metal decking or other leading-edge work is taking place, and it is used to control worker access during those operations. See the Illustration of the Use of Control Lines To Demarcate Controlled Decking Zones (CDZs) for non-mandatory guidance and the requirement in 1926.760(c)(3).

• The CDZ is defined by a control line or any other means that restricts entry.
• Use a CDZ whenever leading-edge decking or initial securement work creates an unprotected edge hazard and access must be limited to authorized workers.

Under 1926.760(c)(3) a control line for a CDZ must be erected not less than 6 feet (1.8 m) and not more than 90 feet (27.4 m) from the leading edge. This requirement is illustrated in Appendix D to Subpart R.

• Measure the horizontal distance from the unprotected/leading edge to the control line placement.
• The minimum and maximum distances help balance worker access to the work area and fall exposure.

Under 1926.760(c)(3) control lines must extend along the entire length of the unprotected or leading edge and be approximately parallel to that edge. See the Illustration in Appendix D to Subpart R for guidance.

• Ensure the control line follows the full length of the exposed edge so there are no unmarked gaps.
• "Approximately parallel" allows for minor deviations to follow site geometry, but the line should closely follow the leading edge.

Under 1926.760(c)(3) each control line must be connected on each side to a guardrail system, wall, stanchion, or other suitable anchorage. This is described in the Appendix D to Subpart R guidance.

• The connection on each side prevents gaps and keeps the control line continuous across the work area.
• "Other suitable anchorage" means an anchor capable of holding the line at the required height and resisting the expected loads—choose anchorage that is secure and appropriate for the site.

Under 1926.760(c)(3) control lines may be ropes, wires, tapes, or equivalent materials, supported by stanchions; Appendix D to Subpart R lists these options as acceptable. See the Appendix D guidance.

• Use materials that are durable for the site conditions and that can be rigged to the required heights and breaking strength.
• "Equivalent materials" should provide the same safety characteristics (visibility, strength, ability to be secured) as ropes, wires, or tapes.

Under 1926.760(c)(3) each control line must be rigged so its lowest point (including any sag) is not less than 39 inches (1.0 m) above the walking/working surface and its highest point is not more than 45 inches (1.3 m) above that surface, as shown in Appendix D to Subpart R.

• Always measure height from the walking/working surface to the line (account for sag and wind).
• If a line sags below 39 inches, re-tension or re-rig the stanchions to raise it within the required range.

Under 1926.760(c)(3) each control line used to demarcate a CDZ must have a minimum breaking strength of 200 pounds (90.8 kg), as stated in Appendix D to Subpart R.

• Verify manufacturers' specifications or test data when selecting rope, tape, or wire so the single line meets the 200-pound minimum.
• Do not rely on multiple weak lines in series to meet the requirement unless each line individually meets the minimum breaking strength.

Under 1926.760(c)(3) a CDZ can be defined by a control line or by any other means that restricts access; Appendix D explains that control lines are one acceptable way to demarcate a CDZ. See the non-mandatory guidance in Appendix D to Subpart R.

• "Any other means" can include barriers, guardrail systems, or clearly marked physical obstructions provided they effectively limit access.
• Whatever method is used, it must reliably prevent unauthorized entry into the leading-edge work area.

Under 1926.760(c)(3) a control line must be connected on each side to a guardrail system, wall, stanchion, or other suitable anchorage; a connection on only one side is not compliant with the Appendix D guidance. See Appendix D to Subpart R.

• Make both end connections secure to avoid gaps or unsecured ends that workers could bypass.
• If a continuous guardrail is not available, install stanchions or other suitable anchor points at both ends of the control line.

No—the guidance in Appendix D to Subpart R is non-mandatory illustrative guidance, but compliance with the underlying requirement in 1926.760(c)(3) is mandatory. Appendix D offers acceptable ways to meet the rule and is titled as non-mandatory guidance in the Appendix D document.

• Use Appendix D as practical examples to implement the mandatory 1926.760(c)(3) requirements.
• If you choose a different but equivalent method, ensure it provides at least the same level of protection as the Appendix guidance.

Under 1926.760(c)(3) control lines may sag, but employers must rig and support lines so the lowest point, including sag, remains at or above 39 inches and the highest point is no more than 45 inches above the walking/working surface, as described in Appendix D to Subpart R.

• Inspect lines frequently and re-tension or adjust stanchions when sagging causes the line to fall below the 39-inch minimum.
• Account for environmental conditions (wind, temperature) that can affect sag and tension.

Under 1926.760(c)(3) it is acceptable to use control lines to demarcate CDZs and those lines may be arranged to create separate restricted sections, provided each control line and each zone meet the Appendix D guidance (placement 6–90 feet from the leading edge, continuous along the unprotected edge, proper anchorage, required heights, and minimum breaking strength). See Appendix D to Subpart R for the criteria.

• Ensure every control line used to create a zone individually complies with the height and strength requirements.
• Maintain continuous barriers so workers cannot accidentally move between zones without authorization or fall protection.

Under 1926.760(c)(3) "approximately parallel" means the control line should closely follow the unprotected or leading edge along its length, allowing for small deviations to accommodate site geometry while maintaining a clear, continuous demarcation, as illustrated in Appendix D to Subpart R.

• Do not create large angles or gaps between the control line and the leading edge where a worker could be exposed to an unprotected edge.
• Use additional stanchions or adjust the path to keep the control line aligned with the edge where the edge curves or changes direction.

Under 1926.760(c)(3) Appendix D states that each control line must have a minimum breaking strength of 200 pounds (90.8 kg), so the individual line—not only the overall system—must meet that minimum. See the Appendix D guidance.

• Select ropes, wires, tapes, or equivalent materials whose individual rated breaking strength is at least 200 pounds.
• Do not rely solely on redundancy of multiple weaker elements unless each element used for demarcation independently meets the 200-pound minimum.

Under 1926.760(c)(3) a properly rigged control line can be used to restrict access to a CDZ for leading-edge and initial decking work, but it is a demarcation and access-control method—not a substitute for a guardrail where the standard specifically requires one; Appendix D explains control lines as an acceptable way to demarcate CDZs. See Appendix D to Subpart R and the requirement in 1926.760(c)(3).

• Use control lines to limit who may enter the zone and under what conditions; where a guardrail is required elsewhere by the standard, comply with that requirement in addition to CDZ controls.
• If workers must perform tasks that require fall protection beyond access control, provide the appropriate guardrail, personal fall arrest, or other fall protection systems as required by the overall steel erection standards.

Under 1926.760(c)(3) employers should check that each control line is 6–90 feet from the leading edge, runs along the full length of the unprotected edge approximately parallel to it, is securely connected at both ends to suitable anchorage, is rigged so its lowest point (including sag) is 39–45 inches above the walking/working surface, and that each line has a minimum breaking strength of 200 pounds—these are the Appendix D criteria. See Appendix D to Subpart R for the guidance.

• Inspect line tension and sag daily or when conditions change.
• Verify anchorage security and that materials used meet the 200-pound rating.
• Ensure the control line extends the full exposed length and that authorized-entry procedures for the CDZ are in place.