The scope (1926.750(a) and (b)) of this federal standard contains a list of examples where steel erection activities may occur, such as single- and multi-storied buildings, systems-engineered metal buildings, auditoriums, malls, amphitheaters, stadiums, mills, power plants, chemical plants, skylights, metal roofs, geodesic domes, canopies, atriums, penthouses, jails and detention facilities. The range of construction activities that may be considered to be steel erection tasks was also considered and listed, such as laying out, hoisting, placing, connecting, welding, burning, and installing metal decking, roofing and siding. The standard’s coverage also includes any procedure that the worker must undergo while moving from point to point in the performance of these activities.
Scope of the StandardThe most significant portion of the standard regulates the safe work practices mandated during the erection of the primary and secondary elements of the structural steel building, normally undertaken by the ironworker’s trade. However, once metal decking and/or roofing is considered feasible during the erection process, the standard is interpreted by many area OSHA offices as potentially regulating the placement, attachment and finishing of metal roof systems. Metal roofing may be considered flatwork, corrugated/ribbed materials or standing-seam panels.
According to the latest OSHA draft compliance directive for compliance officers, the roofing activities must be in conjunction with and contiguous to the structural-steel erection activities. The contract language would certainly be a delineator of this task. If the contract clearly indicated that once the steel erector had completed the structural roof frame a subcontracted roofer was to place the finish metal roofing, then Subpart R would regulate the application of this roof. The roofing contractor could be either a subcontractor to the steel erector or a parallel contractor hired by the controlling contractor.
If the subroof is laid as the last task in the steel erector’s contract and a separate contract is let subsequently by the controlling employer for the finish roofing system (insulation, recovery board, fasteners and finish metal roofing), then these roofing tasks may be considered ancillary, since they do not occur during, or they are not a part of, steel erection activities (1926.750 (b)(2)).
After interviewing OSHA compliance officers in several states, a subtle discrepancy in interpretation of this section became obvious. Some officers stated that if there was a break in the continuity of the scheduled contract work and the steel erector is no longer on site when the roofing tasks are performed, then the regulation of the work would fall under Subpart M: Fall Protection (1926.500), even if the roofing material was metal (steel, aluminum, copper or an alloy). Other compliance officers stated that the metal roofing operation might have to be considered on a case-by-case basis. They consider that a site-specific hazard assessment (job-safety analysis) may indicate that the roofing hazards were more indicative of steel erection than not.
The associated primary roofing activities that OSHA considers steel erection tasks may include: “hoisting, laying out, placing, connecting, welding, burning, guying, bracing, bolting, plumbing and rigging structural steel, steel joists and metal buildings; installing metal decking (roofing), curtain walls, window walls, siding systems, miscellaneous metals, ornamental iron and similar materials, and moving point-to-point while performing these activities.”
The Controlled Decking ZoneThe primary issue to be considered for metal roofing is the standard’s section on the Controlled Decking Zone (1926.760(c)). This is a subsection of Fall Protection and clearly defines an exemption to the required fall protection measures. The CDZ is defined as, “That area of the structure over 15 feet and up to 30 feet above a lower level where metal decking is initially being installed and forms the leading edge of a work area.”
Under Subpart R, whenever a roofing employee is installing metal roofing where he or she can potentially fall fewer than 15 feet to any lower level or exterior grade, then no fall protection measures are mandated. Whenever the roofing activity is above 30 feet to any lower level or exterior grade, every roofer must be protected by a fall protection or prevention system. However, between 15 and 30 feet, the metal roofer who complies with the criteria for work within a CDZ is exempt from the fall protection requirements.
Section 1926.751 of the standard defines this zone as, “An area in which certain work (for example, initial installation and placement of metal decking) may take place without the use of guardrail systems, personal fall arrest systems, fall restraint systems, or safety net systems and where access to the zone is controlled.”
The purpose of the CDZ is to allow trained and authorized metal roofing personnel to work initially placing sheets or panels up to 3,000 square feet in area without having to attach each piece as it is placed. Parallel courses may be adjusted and true edge alignments verified before fastening the material. These workers are permitted to work without tying off their lanyards to horizontal, vertical or retractable lifelines. This may prove to be an invaluable feature of the CDZ as it may prevent exposing workers to inevitably greater trip and fall hazards.
CDZ ConditionsSubpart R lists the conditions that must be met for the fall protection exemption of the CDZ.
- The working level of any portion of the CDZ must not present a fall hazard greater than 30 feet (or two stories) to a lower level, whichever is less.
- Access to a CDZ shall be limited to only those workers “engaged in leading edge work,” which is considered the initial placing of the roof material and the safety deck attachment of each piece.
- Safety deck attachment means, “an initial attachment that is used to secure an initially placed sheet of decking to keep proper alignment bearing with structural support members.” This may be tack weld, bolt, screw, clip or other anchoring device.
- The boundaries of the CDZ shall be “clearly marked by use of control lines” and “shall not exceed more than 90 feet wide and 90 feet deep from any leading edges.”
- Be no less than 6 feet or more than 90 feet from the leading edge being installed. Therefore, if the roof panels are 3 feet wide, then two complete courses should be laid first to achieve the requisite 6 feet of deck prior to the first control line. These panels must be considered outside the CDZ and fall protection would be required during installation.
- Extend parallel along entire length of the (unprotected) leading edge.
- Connect on each side to a guardrail, wall, stanchion or other suitable anchorage.
- Consist of ropes, wires, tapes or equal, with a minimum tensile strength of 200 pounds.
- Be rigged so that its lowest sag point is 39-45 inches above the working surface.
- Unsecured (roof) decking in a CDZ shall not exceed 3,000 square feet.
- Final roof deck attachments shall not be performed in a CDZ. The roofers making final attachments shall be protected by guardrails, personal fall arrest systems, fall restraint systems or safety nets until work is completed. Any roof deck being initially placed or finally fastened on the outside of the CDZ control lines shall be secured immediately upon placing the piece.
- All personnel authorized by the employer for CDZ work shall be trained in the nature of hazards associated with CDZ work and the establishment, access, proper installation techniques and safe work practices within each site-specific CDZ.
Placing of MaterialsThe CDZ is a continually moving area as the 90-foot (maximum) depth is eventually reached. While the roof materials do not have to be placed within the CDZ control lines, they should be placed to enable roofers to obtain sheets without leaving the zone. Before a bundle of roof decking or paneling is initially loaded on the steel purlins, the employer is mandated to install at least one row of bridging with terminal anchors. This ensures that the structure is securely braced to prevent any deflection that could cause the structure to potentially fail and lose support.
Roof deck should also be placed within 1 foot of the end of the purlin or support member. Each decking bundle is limited to a gross weight of 4,000 pounds and shall bear on a minimum of three support members. Any loose materials shall be securely fastened to prevent a falling object hazard. At any time during CDZ work, should the site or environmental conditions dictate (rain, ice, wind, etc.), then the roofers shall immediately secure all the materials from accidental displacement. All materials not removed from the roof at the end of the shift shall also be adequately secured.
Subpart R Fall ProtectionFinal roof connection (screws, welds, clips) shall be made behind the CDZ installers. Non-CDZ roofers are protected from falls from unprotected edges (above 15 feet) with guardrails, perimeter deck safety cables, restraint devices, personal fall arrest systems or safety nets. If the roof deck is less than 15 feet above a lower level, then no fall protection is mandated. Over 30 feet, all roofers must be protected by a fall protection system. It is only between 15 to 30 feet that the fall protection exemption for metal roofers is in effect.
While it is not mentioned in the revised steel erection standard, most OSHA compliance officers consider roofs over a 4:12 pitch to be too steep to permit the use of CDZ methods. Warning control lines would prove inadequate for preventing employees from sliding off the roof. Metal roofing over 30 feet and a 4:12 pitch requires that roofers be protected by one of the following fall protection systems:
- Top rail at 1/4-inch minimum diameter at 42 inches (plus or minus 3inches) capable of resisting 200 pounds minimum force without failure.
- Mid-rail at 21 inches, 150 pounds minimum force resistant.
- Nominal 4-inch-high toe board with 1/4-inch maximum drain space below 50-pounds resistant.
- Screen, mesh or debris netting if a hazard analysis proves small objects may fall on workers below.
Personal Fall Arrest System
- ANSI-approved full-body harness, properly selected and fit-tested.
- ANSI-approved mid-system attachment device such as a shock-absorber lanyard or retractable lifeline.
- Adequate strength (5,000 pounds minimum) anchor point device(s), such as mono-point devices (bream, clamp or trolley), deck-mounted constant-force post anchor, horizontal or vertical lifeline.
- Adequate, site-selected structural anchor point(s) evaluated and selected by the
- Qualified Person to resist 5,000 pounds impact force per attached worker. These anchor points may be already stressed by various dead, live and environmental loads, which should be taken into consideration.
- An employer-designated Competent Person to inspect all systems, evaluate safe work practices and implement the employer’s fall protection plan.
Fall Restraint and Positioning Devices
- ANSI-approved body belts or full-body harnesses with drop-forged steel positioning D-rings.
- ANSI-approved (non-shock-absorber) positioning lanyard.
- 3,000-pound-minimum anchor point to restrain and position the worker, preventing a fall of more than 2 feet, leaving hands free to work and preventing the roofer from entering a potential fall hazard area.
Safety Net System
- ANSI-approved fall protection nets shall be hung by trained and experienced installers as close as possible to the working level.
- Net edge protections could be as far as 13 feet beyond the roof edge, depending on the drop distance.
- Installations shall prevent a falling worker from striking any objects or structure below.
- Nets shall undergo very specific drop tests by a Competent Person anytime they are installed, repaired or moved, and at least every six months.
- Nets shall be inspected once a week, or after any suspicious impact event and cleaned at least every shift. The Competent Person shall evaluate nets for defects or damages that would cause them to be taken out of service.
- Safety nets shall always be chosen as the final fall protection option and only after all other methods prove infeasible.
ConclusionContact the technical compliance officers in your area for any specific interpretations of their compliance directives for Subpart R. These men and women are extremely dedicated, knowledgeable and willing to help. Despite the clich¿it really is a “new OSHA.” I have only encountered professional, cordial,and non-adversarial personnel in my inquiries.
Compliance officers will often admit to learning something new every time they talk to employees or visit a work site. While it is the intent of OSHA to apply and enforce the implementation of the standards uniformly, these directives are often issued after the completion of the final rule and interpretations may vary from locale to locale. Be patient and realize the large areas of responsibility for relatively few inspectors. While Subpart R may not regulate all roofers, those metal roofers who are contracted in conjunction with multi-tiered building project will be afforded many new fall protection options in this revised steel erection standard.