Ch 12 pg 338-344

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Flat timber trusses are constructed with 2x8s or _ bolted together as top and bottom chords, as well as 2x4s or _ web members

2x10 2x6

Bowstring and flat timber trusses are spaced ____ ft apart

20

Flat timber trusses should never be worked on or under if there is ____ fire inside

Heavy

The most common type of lightweight truss has short scraps of 2x4s joined together by means of stamped sheet metal fasteners called a _ nail or ___ plate

Gang gusset Signup and view all the answers

A second style of light weight truss consist of 2x4s or _ top and bottom chords connected by ___ steel webs

2x3 tubular Signup and view all the answers

These light steel elements act as heat . Lightweight trusses biggest drawback is their lack of

Sinks mass Signup and view all the answers

Gusset plates penetrate the wood only about ____in

1/4 Signup and view all the answers

Drilling a hole (up to __ in. In diameter) weakens the 2x4. Second the hole and steel pin allow fire to attack from the inside and outside the wood of the chord

3/4 Signup and view all the answers

A risk to all _____ chord 2x4 trusses is the risk of penetrating the top chord with a power saw blade

Parallel Signup and view all the answers

Parallel chord trusses are often only covered with an ____ of roofing and plywood

Inch Signup and view all the answers

Frank brannigan coined the term ____ loft

Truss Signup and view all the answers

No longer do FFs have __-20 minutes in which to search, rescue and attack before they notice the floor or roof sagging.

10 Signup and view all the answers

Many of the new systems fail in less than __ minutes often without any noticeable sag

10 Signup and view all the answers

The parallel chord beam that consist of a top and bottom chord of 1 1/2x in plywood with a web of in plywood

2 3/8 Signup and view all the answers

One very common type of lightweight roof, especially on _ buildings consist of open web steel bar joist supporting corrugated steel deck. The problem with these roof rest with the steel itself and it’s when heated

Commercial behavior Signup and view all the answers

Steel bar joist are formed by bending a steel bar in a repeating __ pattern

Z Signup and view all the answers

Steel bar joist can be up to _ ft long and may be spaced up to ft apart

60 6 Signup and view all the answers

Ch 17 pg 435 says steel bar joist are spaced 2 to __ ft apart

6 Signup and view all the answers

The roof decking steel sheets averaging in thick, ft wide and __ ft long are sometimes tack welded in place

1/16 3 20 Signup and view all the answers

The insulating material on top of the metal sheets can be either ___ or rubber sheeting up to in thick

Fiberglass 3 Signup and view all the answers

The primary hazard to roof FFs from metal deck roofs is ___ into the vent hole while cutting it

Falling Signup and view all the answers

Sudden catastrophic collapse isn’t as common in ___ joist supported roofs

Steel Signup and view all the answers

Past experience has shown while these roofs fail in less than __ minutes of exposure to heavy fire, they don’t fail suddenly

5 Signup and view all the answers

FFs should us a ____ or solid stream to cool the underside of a metal deck and roof joist well ahead of their location

Straight Signup and view all the answers

“Anybody who cuts through any part of the truss shall be responsible for the _ of repair and ___ calculation needed to ensure stability of the truss”

Cost engineering Signup and view all the answers

Flat Timber Trusses

Flat timber trusses are constructed with 2x8s or 2x10s bolted together as top and bottom chords, as well as 2x4s or 2x6s web members.

Truss Spacing

Bowstring and flat timber trusses are spaced 20 ft apart.

Fire Danger Trusses

Flat timber trusses should never be worked on or under if there is heavy fire inside.

Lightweight Truss - Gang Nail

The most common type of lightweight truss has short scraps of 2x4s joined together by means of stamped sheet metal fasteners called a gang nail or gusset plate.