Fall Protection on Roofs, Leading Edges, and Steel

General fall protection rules assume an edge that stays where it is. Roofing, decking and steel work are different. The edge moves as the job goes on, the surface may be sloped or unfinished, and a guardrail may be impossible to install. OSHA wrote specific rules for these jobs, and they allow options that are not allowed anywhere else. Those options come with tight limits. This is for workers and leads on roofing, framing, concrete and steel crews, and for maintenance staff who go up on roofs. Your employer's plan and your competent person decide what applies on your site.

What You Will Be Able to Do

• Tell a low-slope roof from a steep roof, and list the options for each.
• Set up or check a warning line and a safety monitoring system.
• Apply the general industry roof distances for maintenance work.
• Explain what a leading edge is, and when a fall protection plan is allowed.
• Set the outward reach of a safety net.
• Apply the steel erection trigger heights and the controlled decking zone limits.

Which Rule Applies

Roofs: Low-Slope or Steep

A low-slope roof has a slope of 4 in 12 or less, meaning it rises 4 inches or less for every 12 inches of run. A steeper roof is a steep roof.

Worked example: A roof rises 5 feet over a run of 15 feet.

1. Rise / run = 5 / 15.
2. Multiply by 12: 5 / 15 x 12 = 4.
3. The slope is 4 in 12, so it is low-slope, right at the limit.

The difference comes from how you fall. On a low-slope roof, the danger is mostly at the edge, so OSHA allows systems that keep you away from it. On a steep roof, the slope itself can carry you to the edge. You need protection the whole time you are on it, no matter how far you stand from the edge.

Warning Lines

A warning line is a rope, wire or chain on stanchions around the roof work area. It tells workers where the danger zone starts. It does not stop a fall.

• At least 6 feet from the roof edge.
• When mechanical equipment is used, at least 10 feet from an edge that runs across the direction the equipment moves.
• Between 34 and 39 inches above the surface at its lowest point.
• Flagged with high-visibility material every 6 feet or less.
• Stanchions must resist a 16-pound sideways force without tipping.
• The line needs at least 500 pounds of tensile strength.

A warning line is used with a guardrail, net, fall arrest or safety monitor, and it is not enough on its own. Only workers doing roofing work may go between the line and the edge. Mechanical equipment may only be used or stored where a warning line, guardrail or fall arrest system protects workers.

Safety Monitoring

A safety monitor is a competent person who watches workers and warns them when they get into danger. It is the weakest option, so the rules are strict:

• The monitor stays on the same surface and in sight of the workers.
• The monitor is close enough to speak to them.
• The monitor has no other duties that could distract them.
• Workers must follow the monitor's warnings right away.
• No mechanical equipment is used or stored in an area protected only by a monitor.
• Only workers doing roofing work, or covered by the fall protection plan, may be in the area.

Roof Work in General Industry

An HVAC technician or building mechanic working on a finished low-slope roof falls under general industry rules. Those rules go by how close you get to the edge.

A designated area is a marked space, set off with a warning line, that workers stay inside.

Skylights and Roof Openings

Skylights are holes. They can look solid, especially when dirty or covered with snow, and plastic panels get brittle in the sun. Workers more than 6 feet above a lower level must be protected from falling through them by a cover, a guardrail or fall arrest. Never sit on one or set materials on it.

Leading Edges

A leading edge is an edge of a floor, roof or deck that moves as the work goes on. Each new sheet of decking or new section of formwork puts it in a new place. The workers placing it are the ones next to the drop.

At 6 feet or more, leading edge workers need a guardrail, net or fall arrest. If the employer can show that these are not feasible or would create a greater hazard, a written fall protection plan is allowed. OSHA presumes that at least one conventional system will work, and it is up to the employer to prove otherwise.

Connectors need attention here as well. A line that runs over a steel or concrete edge can be cut in a fall. Use an SRL that is rated for leading edge work, and follow its label on anchor height, clearance and edge type.

Fall Protection Plans

Only three kinds of work can use a plan in place of conventional systems: leading edge work, precast concrete erection and residential construction. The plan must:

• Be written for the specific site by a qualified person.
• Be kept at the job site and kept current.
• Be carried out under a competent person.
• Say why conventional systems are not feasible or create a greater hazard.
• Describe the other measures that will reduce the risk, such as scaffolds, ladders or vehicle-mounted platforms.
• Name the controlled access zones and who may enter them.
• Be changed by a qualified person, and be reviewed after a fall or serious near miss.

Workers not listed in the plan stay out of the zone. A plan is the exception, so do not assume your site has one. Residential crews in particular often think they are exempt. They are covered by the same 6-foot rule.

Controlled Access Zones

A controlled access zone (CAZ) is a marked area where certain work may go on without conventional fall protection. Only authorized workers may enter. It is allowed only under a fall protection plan, or for overhand bricklaying.

The control line stands 39 to 45 inches high, or up to 50 inches for overhand bricklaying. It needs at least 200 pounds of breaking strength, and it is flagged about every 6 feet.

Safety Nets

Nets can protect a whole crew with no action by the workers. They only work if they are placed correctly.

• Install the net as close under the work as you can, and never more than 30 feet below.
• Leave enough room under it so that a person landing in it will not hit what is below.
• Extend it past the edge, as shown here.

Worked example: Your deck is 12 feet above the net. It must reach at least 13 feet out past the edge. An 8-foot reach would be fine only with a net 5 feet or less below the deck.

Testing and upkeep:

• Drop test a 400-pound bag of sand after the net is installed, after it is moved or repaired, and every 6 months if it stays in place.
• Inspect it at least once a week, and after anything that could damage it.
• Remove tools and debris as soon as possible, and at least before the next shift.
• Take out any net with damaged sections until it is repaired.

Steel Erection

Steel erection has its own rule, Subpart R, with higher trigger heights.

• Most workers: protection is required on a surface with an unprotected side or edge more than 15 feet above a lower level.
• Connectors: must be protected above two stories or 30 feet, whichever is less. Between 15 and 30 feet, they must wear the gear and be ready to tie off, whether or not they use it at that moment.
• Perimeter cables: on multistory structures, these go in around the floors as soon as the decking is down.

Connectors and decking crews need specific training under 1926.761, and the options below only apply to them.

Controlled Decking Zones

A controlled decking zone (CDZ) is an area where metal decking is first being installed and forms the leading edge. It can be used at heights over 15 feet and up to 30 feet.

• Only workers doing leading edge decking work may enter.
• Control lines or something equal must clearly mark the zone.
• The zone cannot be more than 90 feet wide or 90 feet deep from the leading edge.
• Unsecured decking is limited to 3,000 square feet.
• Safety deck attachments go from the leading edge back to the control line, with at least two per panel.
• Final deck attachments and shear connectors are not installed in the zone.

Common Mistakes

Check Your Understanding

1. A crew is reroofing a 7:12 house, and the foreman plans a warning line 6 feet from the eaves. Is that acceptable?

No. A 7:12 roof is steep. The options are a guardrail with toeboard, a net or fall arrest.

2. A low-slope roof is 40 feet wide. Can a safety monitor be used on its own?

Yes, on a roof 50 feet or less wide, as long as all the monitor rules are met and no mechanical equipment is in use there.

3. A maintenance tech is checking a rooftop unit 20 feet from the edge, once a month for 30 minutes. What applies?

Fifteen feet or more from the edge and infrequent and temporary work, so the employer can go without fall protection only if it enforces a rule against going within 15 feet of the edge without protection.

4. A net is 8 feet below the work. How far past the edge must it reach?

At least 10 feet.

5. A connector is working on steel 22 feet above the ground. Must she be tied off?

She must wear the equipment and be able to tie off. Above 30 feet or two stories, she has to be protected.

Key Takeaways

• Slopes of 4 in 12 or less are low-slope. Steeper roofs need protection all the time.
• Warning lines stand at least 6 feet from the edge and never work alone.
• A safety monitor needs a clear view and no other duties, and works alone only on roofs 50 feet or less wide.
• A fall protection plan is a narrow exception, written by a qualified person for leading edge, precast and residential work.
• Nets go no more than 30 feet below the work, and reach 8, 10 or 13 feet out, depending on the drop.
• Steel erection triggers at 15 feet, and connectors must be protected above 30 feet or two stories.