MAY TRUCK COMPANY OPERATIONS -- ONLINE BONUS CONTENT
Find the “Safe Zones” & Other Tips for Working on Panelized Roofs
By Randy Frassetto

When it comes to rooftop operations, not all roof systems are created equally. Panelized roof systems are quick to put up, may be assembled off site and can be found everywhere from small commercial structures to million-square-foot warehouses. What’s more: They pose a unique challenge to firefighters. Thus, when it comes to ventilating this type of roof, truck companies must be precise in their operations. Fortunately, our brothers and sisters in the Los Angeles Fire Department have helped in this endeavor by developing cutting sequences and other tactical approaches specific to panelized roofs.

Panelized roof systems have been around for many years and are constructed both conventionally and of lightweight materials. Regardless of style, it’s imperative that you first identify the structural members considered to be “safe zones” and work from these areas for the duration of the operation.

Now, let’s examine the three main components of a panelized roof system so you understand what constitutes a “safe zone”—and what doesn’t.

Main Beams
Main beams run parallel to ledger walls and to shorten the distance that a purlin will have to span. In conventional construction, main beams are made of large dimensional lumber, while lightweight roof systems use a glue lam beam. In both applications, the main beam is supported by an unprotected steel column. Smaller structures, where purlins are shorter, may not use a main beam, and purlins will be hung from ledger wall to ledger wall. On the other hand, large commercial structures may have numerous main beams. Main beams are the most structurally sound component of a panelized roof and, therefore, a good place to operate from.

Purlins
Purlins are structural members that support rafters. These structural members are spaced 8 feet on center and are the support systems from which panels will be hung. Purlins run perpendicular to ledger walls and/or main beams. In conventional construction, purlins are made of dimensional lumber, and in lightweight applications, they’re made of a truss system. Although purlins are not as stout as main beams, they offer an adequate safe zone when not under direct fire impingement.

Panels
Panels are plywood or OSB and have sub-purlins, also called rafters, running across them. These rafters are made of 2 x 4s or 2 x 6s. The purpose of these rafters: to stiffen the OSB and give it support. At the end of each rafter is the metal hanger that holds the panel between the purlins. Panels are often assembled off site, and they may be assembled in sections of panels or set one panel at a time. Crews should not operate on these panels; the hangers and rafters are insufficient to bear firefighters’ weight, and if a sawyer cuts through any part of the 2 x 4 or 2 x 6, there’s no other support (i.e., a bottom cord) to keep them from falling in.

Identifying Safe Zones
Although panelized roof systems may be a challenge to operate on, there are several things roof crews can do to ensure they’re operating safely. It’s always good to check and recheck what we do in the fire service, so use as many techniques as possible for identifying the safe zones on these roofs.

Pre-Plan: The best way to identify what type of roof you’re dealing with is to do so before it’s actually on fire. Many buildings have exposed ceilings for aesthetics, making it very easy to identify a panelized roof. If the components are hidden by a drop ceiling, remove a tile and peek inside. Oftentimes the rafters will be covered with batting for insulation, so look for structural members that are spaced 8 feet apart. Going on top of the roof during a pre-plan will also allow the crew to see the roof from the top, sound for structural members and look for other signs that the roof is panelized (see below) while developing a tactical approach.

Ladder the Ledger Walls: When accessing a roof, ladder on a ledger wall. These are the walls the purlins will be hanging from and are most often the long sides of the building (front and back). Scuppers are often hung on the ledger wall and may be used as a quick clue of which wall to ladder. Since ledger walls are perpendicular to the purlins, laddering here will allow a crew to make their approach on the wall, find a purlin and then work their way to the fire without walking cross-country.

Waffling: After a panelized roof is built, slight sagging may occur on the panels between each purlin. Often, dust will settle in these subtle dips, making purlins and main beams visible by just glancing at the roof. At night, set a box light on the roof to see the natural sagging spots on the roof to help better identify structural members.

Inspection Hole: Once you’ve accessed the roof, cut a 45-degree inspection hole. This diagnostic cut needs to be evaluated to see what type of roof you’ll be operating on. Get up close and personal with the inspection cut and feel around. If you see a rafter, feel in each direction to see if a purlin is attached. If a purlin is exposed, feel around to see if rafters are attached.

Sounding: This is one of the most vital functions for a firefighter operating on a roof with fire underneath. Once you suspect you’re operating on a panelized roof, the sounder needs to confirm that it is indeed that style of roof, and then lead the crew throughout the operation, ensuring everyone remains on structural members. Because purlins and main beams are the main structural components on panelized roofs, A/C units, vent pipes and skylights will be mounted on purlins (and often main beams). These objects may be used as a guide to help identify the location of purlins.

In Sum
The best way to become skilled in identifying panelized roofs and to feel comfortable or confident operating on them is to get outside the station—and onto some rooftops. As companies gain confidence in working on top of these roofs and identifying structural members, operations will naturally become safer and more efficient.

Randy Frassetto has worked for the City of Surprise (Ariz.) Fire Department since 2001 and was promoted to captain in 2005. Surprise Fire is part of the Northwest Valley Firefighters Local 4361. Frassetto has been assigned to Ladder Company 305 for most of his career and he chairs the Arizona Ladder Operations Cadre, which represents most fire departments/districts in the state. This Ladder Cadre was developed to standardize ladder work and further training and research as in pertains to ladder company operations in the state.

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