Gypsum Firewalls and

Other Gypsum Board Construction Facts

OBOA AMTS

DEERHURST

6 October 2009

Bob Mercer CGC Inc.

OUTLINE

• History of the 2005 Change

• Discussions at the SC-FSO

• Attributes of a Firewall

• Alternative Solutions

• Applicability to End Use

• Open Discussion on Gypsum Construction/Installation Issues.

NBCC 2005 Code Cycle

• SC-Fire Safety & Occupancy

• Deliberated the proposal at 4 separate meetings

• Work group struck to identify the intent of the prescriptive provision

• 30 year track record in the USA

• Objective based Code captures intent, function and attributes rather than a laundry list of prescriptive solutions

3.1.10. Firewalls

3.1.10.1.Prevention of Firewall Collapse

1) Except as permitted by Sentence (2), the connections and supports for

structural framing members that are connected to or supported on a firewall

and have a fire-resistance rating less than that required for the firewall, shall

be designed so that the failure of the framing systems during a fire will not

affect the integrity of the firewall during the fire.

2) Sentence (1) does not apply to a firewall consisting of two separate wall

assemblies each tied to its respective building frame but not to each other,

provided each wall assembly is

a) a fire separation having one half of the fire-resistance rating required for

the firewall by Sentences 3.1.10.2.(1) and (2), and

b) designed so that the collapse of one wall assembly will not cause collapse

of the other.

3) A firewall is permitted to be supported on the structural frame of a building

of noncombustible construction provided the supporting frame has a fire-

resistance rating not less than that required for the firewall.

4)Piping, ducts and totally enclosed noncombustible raceways shall be

installed so that their collapse will not cause collapse of the firewall.

3.1.10.2.Rating of Firewalls

1) A firewall that separates a building or buildings with floor areas containing a

Group E or a Group F, Division 1 or 2 major occupancy shall be constructed as a

fire separation of noncombustible construction having a fire-resistance rating not

less than 4 h, except that where the upper portion of a firewall separates floor

areas containing other than Group E or Group F, Division 1 or 2 major

occupancies, the fire-resistance rating of the upper portion of the firewall is

permitted to be not less than 2 h.

2) A firewall that separates a building or buildings with floor areas containing

major occupancies other than Group E or Group F, Division 1 or 2 shall be

constructed as a fire separation of noncombustible construction having a fire-

resistance rating not less than 2 h.

3) Except as permitted by Sentence (4), the required fire-resistance rating of a

firewall, except for closures, shall be provided by masonry or concrete.

4) A firewall permitted to have a fire-resistance rating not more than 2 h need not

be constructed of masonry or concrete, provided

a) the assembly providing the fire-resistance rating is protected against damage

that would compromise the integrity of the assembly, and

b) the design conforms to Article 4.1.5.18.

(See Appendix A.)

A-3.1.10.2.(4)Firewall Construction

Inherent in the use of a firewall is the intent that this specialized wall construction

provide the required fire-resistance rating while also being designed to resist

physical damage—arising out of normal use—that would compromise the rating of

the assembly. Traditionally, this has been accomplished by prescribing the use of

noncombustible materials, which was in fact restricted to concrete or masonry.

Sentences 3.1.10.2.(3) and (4) are intended to retain both of the characteristics of

firewalls, while permitting greater flexibility in the use of materials and designs. The

fire-resistance rating and damage protection attributes of a firewall may be provided

by a single fire- and damage-resistant material such as concrete or masonry, by a

fire- and damage-resistant membrane on a structural frame, or by separate

components—one that provides the fire-resistance rating and another one that

protects the firewall against damage.

If the firewall is composed of separate components, the fire-resistance rating of the

fire-resistive component needs to be determined for this assembly on its own. In

addition, if the damage protection component is physically attached to the fire-

resistive component (for example, as a sacrificial layer), then for the purposes of

determining the overall performance of the assembly, it is also necessary to

determine through testing whether failure of the damage protection component

during a fire affects the performance of the fire-resistive component.

4.1.5.18.Firewalls

(See Appendix A.)

1)Firewalls shall be designed to resist the maximum effect due to

a) the appropriate lateral design loads prescribed elsewhere in this Section, or

b) a factored lateral load of 0.5 kPa under fire conditions, as described in

Sentence (2).

2)Under fire conditions, where the fire-resistance rating of the structure is

less than that of the firewall,

a) lateral support shall be assumed to be provided by the structure on one

side only, or

b) another structural support system capable of resisting the loads imposed

by a fire on either side of the firewall shall be provided.

A-4.1.5.18.Loads on Firewalls

Information on loads on firewalls can be found in the Commentary entitled

Structural Integrity of Firewalls in the User's Guide – NBC 2005, Structural

Commentaries (Part 4 of Division B).

Design No. W314

June 07, 2006(For Vertical Separations)

Assembly Rating - 2 h

Finish Rating - 120 min

ULC W314

2 Hour Assembly Rating

120 min Finish Rating

Design No. W314

June 07, 2006(For Vertical Separations)

Assembly Rating - 2 h

Finish Rating - 120 min

GYPSUM BOARD IS EASY TO HANDLE AND INSTALL

• Allows building structures to be

made from less massive materials.

• Can reduce turnaround and lower

construction costs, especially

in tall buildings.

• Gypsum board systems are up to

80% lighter than alternative systems.

CAN BE INSTALLED IN COLD CONDITIONS

• Gypsum board requires

no cure time.

• Allows construction to

proceed uninterrupted.

• Certain board systems can

be installed year-round.

Advantages

All Weather Construction

Simple / Quick Installation

Erection Sequences w/ Framing

No Scaffolding Required

Accommodates Setbacks & Offsets

Low Labor & Material Costs

Up to 4 Stories High (44’)

Installation