Roofs and Fall Protection – Where’s the Connection

 

Steven P. Bentz, P.E. of Facility Engineering Associates (FEA) provided a lecture titled Roofs and Fall Protection – Where’s the Connection.  Combining roofing basics and the importance of fall protection design Mr. Bentz provided an overview of these topics to the Building Performance Failures and Forensic Techniques class in Archtiectural Engineering at Penn State on November 18, 2014.

 

Experienced in both topics, Mr. Bentz provided a “Roofing 101 introduction  on such topics as:

  • Identification of Basic Low-Slope Roof Types
  • What to look for relative to roofing defects
  • Industry references and sources of information
  • The importance of  proper roof design and detailing
  • Roofing failures

There are numerous references and sources of information related to roofing available to the industry.  An excellent overview, including a discussion of roofing types, roofing design concepts and problem prevention can be found in the in a subsection of the Whole Building Design Guide titled Building Envelope Design Guide – Roofing Systems.

Fall Protection:

According to OSHA, falls are among the most common causes of serious work related injuries and deaths. OSHA requires employers to set up the work place to prevent employees from falling off of overhead platforms, elevated work stations or into holes in the floor and walls.

Employers must set up the work place to prevent employees from falling off of overhead platforms, elevated work stations or into holes in the floor and walls. OSHA requires that fall protection be provided at elevations of four feet in general industry workplaces, five feet in shipyards, six feet in the construction industry and eight feet in longshoring operations. In addition, OSHA mandates that fall protection be provided when working over dangerous equipment and machinery, regardless of the fall distance.  For specific information on OSHA fall protection requirements, regulations and guidelines, link here.

In a similar discussion to Roofing, Mr. Bentz relayed the importance and basics of Fall Protection including explanations of such as items as ”elevated areas”, including relating  how Fall Protection relates to roof systems, design and maintenance.

 

 

 

 

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32 Responses to “Roofs and Fall Protection – Where’s the Connection”

  1. Jim P
    December 2, 2014 at 8:25 am #

    I was curious about how OSHA deals with non-standard (or “innovative”) fall protection setups like the ones here: http://www.fall-arrest.com/ so I did some digging through OSHA standards. It seems one of the few requirements for Dee rings and Snaphooks be that they can take a minimum of 5000 lbs (tested to 3600 lbs without deformation). https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10758
    It seems that as long as the system complies with an accepted test method (like the one here: https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10925 ) it’s OK by OSHA.

  2. Xiaodong J
    December 1, 2014 at 8:01 pm #

    Thanks Mr. Bentz’s great lecture. On the lecture, one of the failure case is about the parapet is pushed off by the drifted snow. Thus, I want to know if there is any recommendations I can use to design a parapet with lateral drifted snow effects. If so how can I evaluate the impact load of sudden drifted snow? Thanks.

    • Shuvrajit G
      December 1, 2014 at 11:40 pm #

      Xiaodong,

      There is a criteria in the ASCE 7-10 regarding sliding snow (7.9) which considers the load caused by snow sliding off a sloped roof onto a lower roof. I think you would need to calculate the additional snow load according to that criteria.

      ASCE also has provisions for snow drifts on lower roof (7.7). In this criteria you need to calculate the surcharge load due to snow drifting from the upper roof in addition to the snow load on the roof.

  3. Jim P
    November 23, 2014 at 3:56 pm #

    How extensive is OSHA’s oversight of small business roofers? It seems to me that I often see roofers working throughout the summer with little or no fall protective gear on.

    • mkev
      November 29, 2014 at 10:09 am #

      I don’t have the answer to that. Perhaps Mr. Bentz has more insight on that one. It is a big construction world out there and OSHA often doesn’t get involved until there is a complaint or accident or someone (a worker) makes them aware a violation is taking place.

  4. Christopher B.
    November 20, 2014 at 10:22 am #

    Are there ever fall protection systems put in place for the roofing material itself (specifically for shale roof)? I ask because I lived in Atherton Hall for 3 years, and it has a slate roof which loses a shingle about once a week. They slide off the roof and land around the adjacent sidewalk, creating what seems like a dangerous situation for people walking past.

    • mkev
      November 29, 2014 at 10:07 am #

      Good point. We should take a look at the slate roofs on campus and if we can document that slate shingles are falling, we can call it in. Temporary netting etc. is often used in those cases where protection is needed until repairs can be made. Pond hall on campus had netting for a number of years while repairs were being planned for the stone parapet. Why don’t you walk by Atherton when you get back and give us an update as part of your second round comment. A number of the slate roofs on campus have been replaced but I don’t know what the status is on that one.

    • Julia H
      December 1, 2014 at 5:45 pm #

      CJ,

      I found a few manufacturers for the debris netting that Professor Parfitt mentioned below. The website I have linked at the bottom showed that there are varying types of netting available for any stage of a building’s life.

      They had nets for new construction and renovation, demolition, historical structures, and bridges, so I am assuming that netting can be specified based on the building’s age, use, and original material. The site also noted that different sizes of holes within the net can be specified, with smaller voids to be used for smaller debris.

      These systems are to be used in addition to fall protection for workers, rather than as a primary means of fall protection, since they are not able to support an individual.

      The netting can be left up for a long period of time, provided it is maintained for. It can also be put up in small areas, so perhaps Penn State should look into small debris nets under each roof with slate shingles. I did a project on a Penn State slate roofed building this summer and noticed a similar issue, so I’m sure this problem persists on many campus buildings.

      http://www.fallproof.com/netting-solutions-debris

  5. Adam J.
    November 20, 2014 at 12:53 am #

    Mr. Bentz provided an insightful lecture on the variety of roofing systems that are in the market today. I found the different application methods very intriguing. It is interesting how they can affect the life time of the roof, mainly around the joints in the material.

    My question relates to coal-tar roofs. Since a number of roofs that are made with coal-tar now require replacement, is there a standard roof type that is commonly used to replace it? During the replacement of the coal-tar roofs, are there any special requirements associated with the removal and discarding of the material, since coal-tar has adverse health effects during the application process?

    • mkev
      November 29, 2014 at 10:02 am #

      Most roof replacement is based on economics or a specific study of the type of builidng. Coal tar was traditionally a flat roof because the same self healing qualities that it has also mean that on steeper slopes, it can “flow” or sag etc. So any of the flat roof products are possible for consideration relative to replacement roofs.

      I would have to check to see if there is any restriction on disposal or recycling of coal tar. Perhaps one of your classmates can investigate that as a second round post. The adverse health impact is when it is heated and applied so removal in itself is not particularly a health hazard as there are no vapors involved.

    • Sam d.
      December 1, 2014 at 9:28 am #

      Relating to the disposal of a coal-tar roof, I found the following resource which includes more information about coal-tar roof safety, and it says that it is not considered a hazardous waste by RCRA (Resource Conservation and Recovery Act) when discarded and that it should be disposed of as required by federal, state, and local regulations:

      http://www.durapax.com/MSDS_Coal_Tar_Roofing_Pitch_3.pdf

      A regulation by the CDC that I found says that coal tar pitch volatiles may be disposed of in sealed containers in a secured sanitary landfill:

      http://www.cdc.gov/niosh/docs/81-123/pdfs/0145.pdf

      • Sam d.
        December 1, 2014 at 9:32 am #

        Apparently a secured sanitary landfill is specifically for hazardous materials, so if the coal tar isn’t considered a hazardous waste, I’m wondering why it needs to go to that type of landfill. I would guess that it’s only non-hazardous in a certain state and could become hazardous as it sits in a landfill or if it is accidentally exposed to certain conditions in the landfill.

  6. Zach B.
    November 20, 2014 at 12:24 am #

    Mr Bentz spoke about how phenolic foam can cause problems when used as part of roof system. Phenolic foam, when exposed to water, can create an acidic component that can speed up the corrosion process when in contact with metal, such as a roof deck. My question is, why would this product even be considered for use as part of a roof system?

    • mkev
      November 29, 2014 at 9:55 am #

      It was a matter of education and experience. No one was giving much thought to condensation. Also, when you put a new roof on, you don’t expect them to leak (but some do). At the same time, they were being pushed as a product with excellent insulation capability which was needed on refrigerator and freezer buildings which is where a lot of the use occurred. The one at Penn State was the food service building. In short, this goes back to our discussions concerning lessons learned from the Hancock building. Be careful when you spec a new material or a new use for an existing material. You don’t want to become the next headline.

      • Todd H.
        December 1, 2014 at 10:39 pm #

        Could the producers of phenolic foam be held financially responsible for damages that resulted its use, similar to the glass manufacturers for the Hancock Building? It appears that they marketed a product without doing complete research to determine its limitations and pitfalls.

        • Adam J.
          December 2, 2014 at 12:18 am #

          Todd, this case was slightly different from the Hancock building since the foam was installed on a variety of buildings prior to the discovery of the problem. The liability associated to the owners could be extremely large given the wide spread popularity of the material in teh 1980’s. According to this article it appears that in 2002, the owners of the companies that produced phenolic foam settled in a class action lawsuit. Each company settled in a slightly different manner, and there were a number of exclusions included in the settlement claim:

          any person or entity whose roof deck is not metal

          any person or entity whose roof system is entirely a standing-seam metal roof system

          any person or entity whose roof deck has already been fully remediated by Manville or Beazer, or who has already settled a claim with Manville or Beazer for damage to his or its roof deck

          class action members who file a Request for Exclusion

          After reading through the article it is unclear on whether or not new discoveries are still eligible to participate in the class action law suit.

      • Zach B.
        December 1, 2014 at 11:23 pm #

        Going in the same direction as what Todd is asking, when introducing a new type of building material to the market, are there any requirements for the manufacturer, or is the liability on the design engineer who specs the new material?

  7. Julia H.
    November 19, 2014 at 11:18 pm #

    Thank you to Mr. Bentz for the informative lecture about Roofing and Fall Protection. I was very interested to learn how the most unsafe materials to apply actually work the best. Learning about toxic chemicals in certain roofing materials and applications left me with a question.

    I was wondering whether there is any correlation between roofing material and degree of fall protection necessary. For example, is there something that reports on how often injuries or falls occur with certain materials, and are those materials considered “less safe?” Are there any codes that are in place to help workers installing a material that is more slippery than another?

    • mkev
      November 29, 2014 at 9:51 am #

      I have not seen any statistics or documents on that topic but in the field we certainly discuss it. Personal fall protection is the key and then there is less worry about the actual material and/or weather that can create a hazard or slippery conditions. As engineers you need to consider it in roofing and reroofing projects. I have seen at least three cases where a slippery new roof (usually PVC) allowed snow to slide off and damage the structure / building where a previous older style roll roofing had more friction and holding power to resist snow slides.

  8. Shuvrajit G
    November 19, 2014 at 10:55 pm #

    Mr Bentz’s talk on roofs and fall protection was very interesting. I had a few questions about the fall protection systems. Are there any tests done to test the reliability of these systems (not the routine load tests) maybe by the manufacturer? Also how often are these systems replaced/ upgraded in a building?

    • mkev
      November 29, 2014 at 9:46 am #

      If you are talking about the personal fall protection devices such as the harness etc., those are tested and rated by the manufacturers. Custom designed anchors in the field require load testing most of the time. They are inspected on a regular basis but not likely changed unless there is a code required upgrade. More often, they get reviewed and updated when there are reroofing projects or major roof top equipment changes etc.

    • Nick D
      December 1, 2014 at 1:18 pm #

      The link below is from a resource provided by a manufacturer. It sites that parts of the equipment including control systems should be inspected at least once a year. The website also states that active fall protection systems shall be reviewed and inspected once every 5 years.

      http://www.fallprotect.com/services/fall-protection-system-recertification/

  9. Tyler P.
    November 19, 2014 at 9:34 pm #

    Thanks to Mr. Bentz for the Roof Enclosure lecture. It definitely opened my eyes to a portion of a building that seems to be often forgotten about. I agree that it is one of the most important areas though because if the roof fails, it is more likely for the rest of the building to fail.

    There are a few questions that I have about the roof enclosure. Typically, whose responsibility is it to detail the sloping of the insulation, is this done by a specialty engineer? Also, I have heard of slightly sloping structural members to aid in the draining process, is this common, or is it typically cheaper and more efficient to just do the sloping with insulation?

    • mkev
      November 20, 2014 at 10:59 pm #

      Generally the roofing (not structural roof framing)slopes are shown on the architectural plans and thus the architect is usually responsible but they need to work in conjunction with the engineers (MEP to determine how many drains, what capacity, and structural – is the structure sloped and how much). If a roofing consultant is on board, they may do that work and sometimes the roof system manufacturer is consulted.

      Sloping the structure is an excellent way to get positive roof drainage. That works well on nice rectangular buildings especially if they slope only one direction (front to back – high to low for example). As you get more complex geometries and obstructions (pent house, elevator overrun etc.) or framing gets reversed in direction for some reason, it gets more complex. But structural slope for the main direction and insulation infill slope for the other direction to get water to the drains is a good combination.

      When you have a flat roof or one that is difficult to slope structure, you have little choice but to do it all with sloped insulation. Odd shaped roofs with many obstructions can be very complex even with insulation.

  10. Sam d
    November 19, 2014 at 2:25 pm #

    Thank you Mr. Bentz for an interesting and informative lecture on roofs and fall protection.

    I am curious about maintenance issues. It seems like there are a lot of roof issues related to poor roof maintenance such as clogged drains, displaced insulation and membranes due to wind, etc. Are there any standards of care for those who manage and maintain a facility to fix those issues every so often? Would it be considered negligence if no one ever unclogged the roof drains and it caused big problems? It seems to me like proper roof maintenance is just as important a factor as the original design.

    • Caroline K
      December 1, 2014 at 10:58 am #

      Sam, I would think implementation of maintenance is entirely dependent on the building owner and their level of care. For example, Western Kentucky University has a roof maintenance plan online that describes the necessary checks and inspections that need to be done on a regular basis:
      https://www.wku.edu/facilities/documents/roof_maintenance_plan.pdf

      I found many other consulting companies that help with formulating a roof maintenance plan and even offer the maintenance services themselves. This link provides guidance on how to create a roof maintenance plan:
      https://www.spri.org/pdf/How%20to%20Implement%20A%20Roof%20Maint.%20System%202006.pdf

      The link discusses that roof systems typically have warranties that are voided if maintenance isn’t done regularly. I am unsure as to whether this is a well-known fact or not, however.

  11. Caroline K
    November 19, 2014 at 12:49 pm #

    Regarding flat roofs, how common is it to see improperly sloped insulation? Is the insulation slope ever calculated correctly but installed incorrectly? Are there ever instances where the roof isn’t structurally sloped at all and only insulation slope is provided?

    I am also curious about where roof systems seem to be heading in the future. Which system is likely to be used the most in the upcoming years? Are there any new systems that haven’t been implemented on any projects but may become more popular in the future?

    • Tyler P
      December 1, 2014 at 8:25 am #

      Caroline, I am not sure where roofs are heading in the future, but I was looking up new roof assemblies and found the following link.

      http://www.kemper-system.com/US/eng/applications/new-roof-assemblies/

      It seems like these would be something that will become more popular due to the adherence to all structural materials, ability to resist ponding, and the fact it is a renewable resource. There are examples of buildings that used this system to solve challenges included in the link.

    • Yewande A
      December 1, 2014 at 7:21 pm #

      Caroline, poor installation and workmanship is one of the problems encountered in the installation of flat roofs and important details like the insulation slope could be missed.
      As with many building components, there is ongoing research in the roofing industry focusing on improving sustainability, energy efficiency, improving the life cycle cost and recycling opportunities for new roofs. In addition to Tyler’s comment, the Center for Environmental Innovation in Roofing have some information on upcoming research into new roof systems presented in the link below.

      http://www.roofingcenter.org/main/Research/Articles

    • Xiaodong J
      December 3, 2014 at 10:47 am #

      “Hi, Caroline, about which system would likely be the most common one, I think it depends on which building the roofing system is serving for.

      For single house, the Asphalt Shingle is the definitely still the most common one. But for other low-slope roof buildings, I think Mod Bit would become the most common one, because the use of BUR will decrease, and Mod Bit has the advantage of cost efficiency, low required maintenance and easy procedure of repair. Also there is a roofing guideline link I found on GAF website.
      http://www.gaf.com/Roofing/Commercial/Guide_To_Low_Slope_Roofing_Systems
      About the new roofing systems, even though some of them come with “green” or “sustainable” titles, they are not likely to become the most common ones. Because of the cost efficiency and maintenance issues. And usually the ones titled as “green” are just for the special requirements of some buildings due to the performance or LEED requirements (everybody likes LEED). The mar! ket of new roofing systems is developing but still small.”

  12. Todd H.
    November 19, 2014 at 10:57 am #

    Thank you to Mr. Bentz for the lecture on Roofs and Fall Protection. It was very informative on a portion of the industry that students typically do not learn about.

    In relation to the fall protection devices, how common are accidents and injuries when they are being used? Are these accidents typically due to improper maintenance/testing of the equipment? Or improper use by the victim? Or a combination of both?

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