By: Joe Contreras
When planning a building envelope restoration project, it’s important for the building owner to understand the effect the proposed project will have on the current fall protection guards at the perimeter edges of terraces, balconies and roofs. When the guards in these areas are structurally sound, they are often left untouched or forgotten about. However, these structurally stable existing railings may not meet the current standards and requirements of ever changing building codes and may need to be replaced or altered to do so. These replacements or alterations can lead to additional costs that can cause a typical building envelope project to quickly exceed the restoration budget.
A majority of buildings in urban areas like New York City have flat roofs that allow for both public and building personnel access. As per the 2014 NYC Building Code, a building that is greater than 22’ tall with a low-slope roof (less than 2.4:12) must have a 42” guard at the low-sloped setback perimeter. Generally, these low-slope roofs have either a solid masonry wall, known as a parapet, or another type of railing system around the setback perimeter. Although the 2014 NYC Building Code mandates that a fall protection guard be at least 42” above the finished deck height, there are instances when a guard that is not 42” high is “grandfathered” or deemed sufficient. In order to appropriately budget for repairs and to plan for this additional work early in the design phase of the project, building owners should consult with a qualified building envelope professional to better understand whether alterations to or replacement of the existing guards are warranted.
Generally, railings and fall protection guards are left untouched until either a parapet or roof replacement project is performed. In order to meet new energy code requirements, a roof replacement project often entails adding layers of insulation on the top side of the roof deck. This ultimately elevates the walking surface of the roof and shortens the distance between the top of the walking surface and the top of the fall protection guard. Using this example, a building owner who has a current parapet height of 42” wants to replace the main roof membrane that’s at the end of its useful life. The entire roof system would need to be removed down to the concrete roof slab before installing a new roof system that meets the current building code requirements. In order to meet these insulation requirements, the new roof system would have to have 4” of new roofing insulation. This additional 4” of insulation would shorten the distance from the top of the new walking surface to the top of the fall protection guard by approximately 4”, leaving the newly established height of the existing guard at approximately 38”. Increasing the height of the fall protection guard by 4” to account for the new roofing insulation now means additional and unforeseen costs.
While building codes change, the most recent 2015 International Building Code (IBC) that predominantly governs railing assemblies mandates that all terraces, balconies and roofs have perimeter guards measuring at least 42” in height from the top of the walking surface. (2015 IBC 1015.7) The new code also requires that railings and guards can withstand a force of 50 pounds per linear foot in any direction and a force of 200 pounds concentrated in any single location along the guard. Under the 2015 IBC, guards may not allow for a passage of a 4” sphere through the vertical balustrades, nor allow for the passage of a 4 3/8” sphere between the top rail and lower components of the railing assembly. This is considerably less than the 8” sphere requirement of the 2006 IBC.
It’s important to note that railing requirements not only affect areas of public use or areas accessible to the public; but also, mechanical areas and roofs that building personnel have access to. These areas are generally governed by OSHA railing requirements instead of IBC. OSHA requirements are less stringent in regard to railing assemblies than the 2015 IBC. Under OHSA requirements, a railing or guard height must be between 39” and 45” above the top of the walking surface and only requires one mid-rail as opposed to multiple balustrades (OSHA 1910.28). Instead of passage of a 4” sphere as defined under the IBC, OSHA regulations limit the passage of a 21” sphere between the mid-rail and either the walking surface or the top rail of the guard.
As a rule of thumb, building owners should understand how their proposed building envelope restoration project affects the overall height of the edge protection and its compliance with current building codes. They should also retain the services of a building envelope consultant to assist in the project planning and design to ensure that any alterations to the building’s railing or guard assemblies are anticipated and properly handled.