FAQs

FAQ Topics / Roofs


Do our employees performing general maintenance tasks on the roof of our facility need fall protection? Our roof has no railing, etc.


Yes! You do need fall protection on a commercial roof for maintenance but
how much depends on your sensitivity to protection and the company’s awareness of recognized fall hazards.



Can you answer the following questions on Fall Prevention?

q.1 – Can there be a painted stripe on the roof for a warning line?

q.2 – Why does the tensile strength of the warning line have to be so high when

the stanchion only needs to withstand 16# of force? This is the standard we

design to and force vectors are involved.


A.1. – Painted lines are a problem in a snow belt and obviously where aggregate is on the roof. I prefer painted lines for permit requirement. The warning

line if permanent does the trick for the permit closer than 6,10 or 12 ft as

necessary. The raised line is a tactile system designed to get the attention

of someone backing into an opening or toward an edge. Roofers are notoriously

backward walkers in unrolling their material and may not see or comprehend a

line when the edge cannot be seen directly.

A.2. – The strength comparison is interesting.
1926.502(f)Warning Lines: 16 lbs vs. 500 lbs. The line has a sag in it

depending on length but the lowest point is 34″ and highest 39″. Therefore the

stanchion is tested at 39″ to see if the tipping force exceeds 16 lbs. First

it should stay upright under reasonable wind conditions (up to 40 mph??),

Second when the bow is taken up as a person backs into it the tipping is an

event designed to get the notice of the worker before the worker gets too

close to the edge. If the fall occurs at 5 ft from the edge, the person should

still stay on the surface; however below 4 ft it is doubtful. Thus 10 or 12 ft

is more practical a distance from the edge.

Ropes and cables always are rated in excess of their minimum because they

degrade. Secondly the ease of having a 500 lbs rope (3/8″) or cable (1/4″)

makes the number work for visibility. The flagging every six feet increases visibility.

The problem of stumbling backwards throws the business of warning lines into a

fundamental conflict. 15 ft or more stumbles backwards are not uncommon and

one can only hope that a warning line causes the person to fall prone. The

best advice is to use a guardrail or parapet for protection.



My question is based on your Tip of the Week #70 that discusses when window cleaners are at 6 feet from the edge and closer. My understanding is that distance doesn’t matter, they need fall protection at any distance from the edge. Am I misunderstanding something here?


Window cleaners are part of the general industry regs and other workers typically are construction reg related.
Workers typically come back periodically for window cleaning purposes.
Therefore 6 ft plus for building edges less than 42″ high seems reasonable in normal ambient conditions for window cleaners. Construction folk, including roofers, can wander the length of a building floor or roof to communicate visibly over an edge unless they are constrained by barriers and work rules in the area where their work occurs. OSHA will deal case-by-case with reasonable interpretation of its construction rule to barricade all floor edges or work areas.



What is the proper distance from the roof edge for a warning line?


15 feet from an edge to locate and mark a warning line is an OSHA interpretation which makes sense to me.

The recent and long ago interpretations on roof work by non-roofing workers starting with the early one in the third edition of Dr. Ellis’ book “Introduction to Fall Protection”, indicate that 15 feet makes a non-roofing violator more noticeable than 6 or 10 feet for roofers.



What is the safe distance from a roof edge for those doing work on the roof (not installing the roof)?


None, workers are drawn like magnets to edges but take a look at the OSHA interpretation in Dr. Ellis’ book of what is reasonable. You can set up your own procedures which if enforced will be effective and OSHA-acceptable.

Be sure to have a review with a compliance officer when you set up.



I’m a member of the Engineering Practice Specialty Group and work in General Industry. I’m not very familiar with fall protection in regards to roofs. We have contractors who have to get on the roof to service air units or make roof repairs. Some of the air units are located about 15 foot from the edge. Can you provide some guidance on regulations and/or best practices for protecting workers from leading edge work hazards?


You can follow OSHA interpretations concerning 15 foot warning line from an edge for non-roofers working on roofs. You can always offer a more protective solution such as a fall arrest system. If your HVAC unit is 15 feet from an edge, you need a space to walk which is at least 3-4 ft closer to the edge than 15 feet and a warning line may not be appropriate for that trade.



I have a flat, corrugated, metal roof at my facility. At the top of our mixing tower, about 5 stories up, there is an emergency escape door. If one were to escape through this door they would walk about 20 feet potentially along the roof edge and then down another ladder to another roof top and again walk about 50 feet potentially along the roof edge to
another ladder which would take them to the ground. All several stories above the ground.

An ISO auditor has told us we need guardrails along the edges of the two roofs leading to the ladders.

Now, my questions: Can I use a rope and some posts to guide employees to the ladder safely or does the guardrail have to meet guardrail standards?

No one performs work on this roof without proper fall protection so this is only needed in case of an emergency evacuation of maybe 1 or 2 employees at the most. Vary unlikely that in an emergency they would be at the top of the mix tower and need to escape this way.


The final decision should be made based on a professional hazard
assessment. No, you cannot stick up some posts and rope guide for
emergency use because an unsteady flexible railing could tip you over
especially in a panic situation. Can you use escape systems like the
vertical chute already hinted – possibly yes but how many years will this system be up and who will inspect it and provide a regular test run and restore it to readiness? Maybe a cable escape system would be easier for one or two persons and those are under the ASTM E06.77 standard – the committee member list is composed of most of the manufacturers in the world who have held themselves to a very high standard but will the owner adopt those same standards for regular inspection and for how long? For you and your plant operation, I suspect it should be a catwalk and railing meeting A1264.1 and OSHA 1910 regs which will be an investment in your plant capital equipment and will meet the IBC and NFPA 101 exit access and discharge requirements. Also maybe another
route is possible depending on the hazard and foreseeable time for
egress. Ladders from roof to roof are very suspect to loosening of the bolts to the structure over time so a professional engineer should design the bolting to last for 20 years without pulling loose and also, once up, inspected annually by a competent person following ANSI A14.3 and 1926.1053 and 1910.27.



Over the years I have heard that one must restrict access to roof edges or provide fall protection for persons involved in maintenance work on roofs to a distance of 6, 10, and 15 feet. Today when I searched 29 CFR 1910, I found nothing specific to roofs and fall protection.

If you are aware of specific applicable language in 1910, or if there is a letter of interpretation regarding this type of work I would appreciate hearing from you.


There is nothing in 1910. 1926 however is more helpful eg 501b1, 2, 10, 15 and 501c also 502 f, g, h, j, and 503a. 1910 is dealt with using 5a1 and 2. Also ANSI A10.18 and A1264.1, 2 hit on the same issues.
OSHA often cites standards in the alternative just in case maintenance is really construction or vice versa.



Are workers allowed under OSHA to work between an unprotected edge and the warning line (the warning lines being set up 6 feet from the unprotected edge)? Is that what the safety monitor is for?
I see for low sloped roofs that there are combinations of guard rails and warning lines, safety nets and warning lines, and fall arrestment and warning lines. How do these combinations work, like for guard rails and warning lines? Where there are no guard rails, you would have to use warning lines, but what about work between the unprotected edge and the warning line? I’m just trying to understand what OSHA envisioned with the standard.


No, the workers cannot work between the unprotected edge and the warning line without a positive form of fall protection.
They must stay within the confines of the warning line for this administrative control to be feasible.
The safety monitor is used to ensure that workers do no leave the confines of the warning line boundary.



I have perused through the proposed rules and it appears that we would have
a choice of fall protection to choose from — guard rail system, safety net, personal fall
protection system,travel restraint, and having employees work in a “designated area”. But the standard does not
specify a distance from the edge that is considered safe, or at least I could not find it
anywhere. So, my assumption is that the employer would then be required to use some kind of
judgement to determine this “safe distance”?
As to the type of work our employees would be performing;
basically it would be
maintenance, preventive maintenance, repair, replacement, etc. for HVAC units. Most of these units are in the middle of the roof, probably 40-50 feet from the edge. But we do have some exhaust stacks that approach the 5-6 foot distance from the edge.

We have no sky lights, so thankfully I do not have to worry about them.

I wonder if we couldn’t put a warning line at a 6 foot distance from the edge and then put
railing around anything else that would be outside the warning line. We currently control
access to the roof and require a permit with a pre-work safety plan to gain access. This plan
would include “you cannot go past the warning line without additional fall protection approved by the EH&S…………….”.


You can do what you want from this selection but only if you can
prove it works. 1910 requires a guardrail to protect an edge. There is no choice from loading docks and up (removable if blocked with a truck). Apply
the control zone out of 1926 – you can go 15 ft unless a trade is specified e.g. roofer 6 feet. This is based on the human factors of the work being done.
You can always test it with your Consultation OSHA folk if they answer quick enough.

Check out the OSHA Instructions to the Field and Interpretations. You can
search them with key words.

The higher the danger the higher the training if you want to give up more fancy solutions.



My question involves once you fly personnel in a man basket to the top of a roof what to do when letting the man basket down on the roof.

The personnel need to exit the man basket once on the roof to walk on the roof. There is nothing else to tie off to but the man basket once on the roof. Can we tie off to the crane hook that set the man basket on the roof? Is it legal to tie off to a hydraulic crane hook?


This not an official answer from any authority just my own sense of what is possible.

Several questions come up:

1. What is the work? Might there be other types of work  what?
2. What is the frequency of this work?
3. How many workers do you want to have anchorages for?
4. How big is the roof? assuming low slope with no equipment or obstructions?
5. You are following 1926.550 for the basket and crane – correct?
6. Do you want to hook to the crane hook itself  how?
7. How high is the crane hook over the roof?
8. What is the height of the crane?
9. Could you set up a control zone instead, after landing the basket well away from the edge?
10. Can you lock out the crane before it is used for the anchor point?
11. Do you intend to use SRLs?
12. Is weather or the environment a factor?
13. Could you lift an AEP Raptor to the roof as an anchor (no over the side work)  check with CalOSHA if they have approved yet for roofer work
14. Anything else to add?



We will be installing a hatch on the roof of one of our existing buildings. Currently there is no other means of accessing the roof. The building currently has a 2 foot parapet around it. Do I also need to install a guardrail around the perimeter of building if we will be sending employees/contractors to the roof for maintenance (i.e. drain cleaning, etc.) or roof repairs?


Recognize and solve the hazards before rushing to the regulations. This is your
opportunity to do best practice because if you aim for one type worker or trade another visit or trade will let you see the need for a general solution. There are 28 trades minimum who might visit a commercial roof over the building lifetime. This may well be a permanent fix not a temporary fix.

A. Roof Hatch: ANSI Std A14.3-2008 sec 5.3.4.3 requires handles for access. Corps of Engineers EM385-1-1(2003) required horizontal grab bars for all
ladder access.
Review Ladder Improvements section of this website including roof hatch walk in walk out features.
If you cannot discipline closing the hatch or reducing the opening then the guard is good.
Note the two hazards: 1. Falling from the ladder while
accessing in or out needs horizontal grab bars while falling in the opening
from the roof is a second hazard. Walmart have the HatchGrip on several thousand roof hatches of their super stores currently. The need for horizontal grab bars is critical for life safety. Read the Three Point Control white paper under What’s New section of this website with Human Factors article reference and Ph.D thesis from Justin Young this year at UMich which essentially says
only hold the horizontals and never the verticals because you will slide under fall conditions. 2. Falling from the roof into the hatch is an issue calling for guardrails. Note access to a roof by someone is inevitable including the owner.

B. Parapet 3.5 ft or higher should be designed into your two foot existing – a qualified engineer must do the calculation (EFSS can do this). Roof
edge: requires protection for the life of the building. Contractors cannot be economical in providing guardrails and they will not be bid unless a line
item. If the roof hatch ladder is on the outside wall – the hatch needs to be moved in side to another structural wall. Too many outside walls are installed with a hatch allowing access to step over the building edge.

If the present parapet cannot be extended: There are a number of systems for edge protection which because of weighted stanchions and rails or bolt-on
edge verticals to support railings are available and well established. For long term you want a twenty year life – talk with the manufacturer directly about lifetime.

Note: Don’t forget skylights if present – they must be protected with metal screens to safeguard against plastic UV deterioration – follow the rule in
1910.23 and not the Martin interpretation (does not address uv exposure). Now is a good time. Again 20 year fix permanently attached over existing
dome skylights – otherwise a lethal exposure.



Has anyone addressed roof fall protection by semi-permanently installing portable guardrail systems? Beyond protecting the roof surface and following the manufacturer’s installation requirements, is there anything else that comes to mind?


Yes: good idea for existing commercial roofs. But watch out for one section only! Must be a right angle of railing lengths or it only takes a low force to tip over. Don’t use for fall protection anchorage without analysis.

Encourage architects and engineers to protect permanently or
semi-permanently for new and existing commercial buildings. As cell
receivers and transmitters increase: the greater urge to do it now. But anyvisit to a roof for maintenance/inspection makes the roof a workplace. Use the OSHA exposure-based 1910 interpretation of guardrails v. fall arrest to see if you comply.



I had another question come up regarding safety with ladder access roof hatches.
Can you provide input regarding how to safely unlock a roof access hatch from a fixed vertical ladder? Is it even possible to maintain the proper points of contact while on the ladder trying to open up a padlock? Does OSHA have guidelines specific to this potential safety issue?


Depends on the lock and its complexity and whether it is well lubed with silicone.
Other important include:
Where is the anchor point for attaching short lanyard?
Where is the platform for standing?
How far is the platform from the hatch?