TRUCK COMPANY OPERATIONS
By Randy Frassetto

In the ventilation world, truck companies need to be proficient on all types of ventilation tactics. A fire department may favor one ventilation style over another (vertical vs. horizontal), but all truck companies should know how to do both safely because we can’t assume one style will work for every situation. Further, it’s important to remember that all ventilation operations are only as good as our resources, training and associated plans.

Keeping all this in mind, in this article, I’ll address effective ways to ventilate a panelized roof using a two-sawyer louver.

The Importance of Preplanning
The best time to come up with a plan is before the fire. A panelized roof system has more hazards than a parallel cord trussed roof, so a successful roof operation won’t happen unless it’s well thought out and rehearsed.

After arriving on scene, you’ll need some information to help formulate your plan. Get on top of the roof and see if structural members are waffling, how A/C units are arranged, where vent pipes are situated (certain vents may be a clue to what’s underneath them, like the kitchen) and any other pertinent information you may need. It’s a good idea to sound around up top with trash hooks to see what the roof feels like. Once you have an idea of the layout of the roof, go inside and see what you have. Note the ledger walls and see how many main beams are in the structure. Also look at structural members to see what they’re made of.

Structure or Contents Fire
After arriving on scene, members need to quickly determine whether they are dealing with a structure fire or a content fire. Read smoke, listen to interior reports and read the roof to determine if you’re working over a contents fire only, or if fire has made it into the roof’s structural members. In a contents fire that has not yet involved the roof members, flashover is the most likely catastrophic event, and effective and aggressive ventilation will help prevent this from happening. In heavy fire conditions that have gotten into the structure members, a rapid roof collapse could occur. If the roof isn’t tenable to operate on, someone must determine if it’s safe for crews to work underneath it.

When operating on a panelized roof with lightweight structural members, make your cut over pressurized smoke—not fire. It’s important to remember that although conventional constructed panelized roof systems have beefier structural members that will last longer under fire conditions, the weak points are the panel and rafters that rest between the purlins.

Pre-Determined Positions
Safe and effective operations on a panelized roof will need to be well coordinated with four crewmembers performing specific roles. The four-person crew can break into two groups of two, each consisting of a sounder with a trash hook and a sawyer with a chainsaw. Following are proposed roles for each person:

Sounder 1: This crewmember is responsible for leading the crew along the ledger wall and identifying the structural members that will be operated on. It’s their job to determine the location of smoke-indication holes and read smoke accordingly to determine the location and size of the vent hole. It’s important that the sounder ensure that all ventilations operations are being conducted from structural members. Once the hole is cut, Sounder 1 will assist in louvering the panel.

Sawyer 1: After Sounder 1 determines the proper locations, Sawyer 1 will perform the diagnostic cuts (45-degree inspection hole and smoke-indication holes). Once the ventilation location has been reached, Sawyer 1 will make the back cut to identify the rafter (also called the stiffener or sub-purlin) where the operation will begin. To prevent the two saws from touching, this sawyer will always start the cut sequence and determine the pace at which the hole is cut.

Sounder 2: The main function of this sounder is to ensure that their team remains on a structural member (this will be 8 feet across from the other team when operating on purlins). When Sawyer 2 is cutting, Sounder 2 must ensure that the sawyer remains on their structural member. Once the hole is cut, Sounder 2 will also assist in louvering the panel.

Sawyer 2: This crewmember will mimic what Sawyer 1 is doing, with the exception of the back cut. It’s important that this sawyer waits for Sawyer 1 to begin the cut and pick up where they left off to complete the louver.

The Cut Sequence (See Photos at Left)
Once the two teams have reached the ventilation hole location, Sawyer 1 begins making a back cut to identify a rafter. After the rafter is marked, Sawyer 1 cuts parallel along the rafter toward the purlin that they’re standing on.

Once Sawyer 1 begins their cut, Sawyer 2 can start their sequence from where the first cut was made, cutting back to the purlin that they’re standing on. This will give an 8' head cut between the two purlins. (Note: It’s important for both sawyers know the other’s reach so a complete cut is made. They’ll be able to reach farther in a more stable manner if they really lower their rear ends. Also, it’s best to use a 20" chainsaw bar for ventilation.)

Now that each sawyer has cut back to the purlin they’re standing on, the down cuts need to be made parallel to this purlin, ensuring that all cuts are crossing each other. Both sawyers will roll one rafter and stop and roll the second rafter for a 4' cut.

Sawyer 1 will then cut along the inside of the rafter that they stopped at. Sawyer 2 will repeat the same cut, completing the sequence for that one panel.

At this point, a back cut is no longer required for additional cuts. The next hole can begin with Sawyer 1 making the first cut on the other side of the rafter on which their previous hole just ended.

Try to let the sawyers cut two panels before louvering begins. This way, you’re not blinding them with smoke and introducing an influx of heat into the operation.

Once the ventilation operation is complete, the sawyer and sounders switch tools so that the sawyers can now lead the crew off the roof in the same direction that they first approached it. Smoke-indication holes should be monitored during the entire operation, and a second means of egress should already be established.

Summary
This operation is very efficient on a panelized roof, but it must be well thought out and orchestrated in a training atmosphere for it to be successful during a real incident. It’s a good idea to build a panelized roof prop so that the sawyers can get familiar with their cutting sequence and comfortable being ambidextrous with the saws, and also to ensure proper depth, with the ability to feel and roll rafters during the operation.

But ensuring that the sawyers can cut is just one part of the equation. Crews can also pick a building and walk through the entire operation, simulating everything from laddering the building to sounding out structural members along the path they’ll move across on the roof. It’s important that crews never “jay-walk” during any roof top operation.

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.

Copyright © Elsevier Inc., a division of Reed Elsevier Inc. All rights reserved. SUBSCRIBE to FIRERESCUE