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Playing With Fire

What do you really know about protecting your business and staff from the threat of fire? Test your knowledge of firestopping here . . .


January 1, 2001  


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Fire is one of the most beneficial tools that humankind has, and one of the most lethal. Fire protection is serious business — deadly serious, and every major building code out there exists to reduce the threat of fire.

Fire protection encompasses three broad areas: prevention, containment and suppression. The distinction between containment and suppression is the distinction between passive and active protection systems. Passive systems protect by virtue of their inherent properties, while active systems rely on external energy sources such as electricity, water pressure or human intervention.

Firestops are an integral part of any fully implemented containment system — the principal strategy embodied in all building codes and life safety. A firestop must satisfy a number of requirements to be effective:

it must be able to meet the same fire resistance rating as the barrier in which it will be applied;

it must accommodate the penetrating items, including any requirements for motion or thermal expansion;

it should function as a smoke and gas barrier;

it must be reasonably easy to re-penetrate to accommodate building service modifications; and

it must be cost effective.

BASIC DEFINITIONS

Ratings

An “F” (fire exposure) rating, given in full hours, indicates that the test assembly withstood the standard fire exposure without penetration of flame or spontaneous ignition on the unexposed side for the indicated period. This rating also indicates (except in Canada) that there was no passage of water to the unexposed side during the hose stream test.

An “H” (hose stream) rating is given in Canada only to indicate separately that the assembly passed the hose stream test.

A “T” (temperature) rating, given in full or fractional hours, indicates that no temperature on the unexposed side increased over ambient by more than 325F for the indicated period. Measurements are conducted on the penetrating item and the firestop seal itself. A “T” rating may be zero, but it can never be more than the “F” rating.

An “L” (leakage) rating given in CFM/SF indicates the amount of air leakage at various temperatures to simulate hot and cold smoke. This rating is used to demonstrate the code requirements for the smoke wall sealing capabilities of the firestop material.

An assembly is a wall, floor, or other partition, with or without penetrating items such as receptacles, outlet boxes, recessed lighting fixtures, pipes, cables, conduit or ductwork. This assembly will have been deemed to be fire rated, and the details of the assembly must be spelled out in any approval.

A system is the combination of the assembly, the penetrating item(s), and the firestop material that will be effective for that combination. All items together constitute the system, and that combination is the basis for classification by a testing authority.

Intumescence describes the characteristic of a firestop material to form a high-volume, insulating char upon exposure to fire or elevated temperatures. This is a key property of an important class of firestop materials. The resulting char should be strong enough to resist the turbulence of a severe fire, and insulate well enough to protect the underlying surface.

THE FIRESTOP CIRCLE

Although firestopping has been a viable containment vehicle in fire protection for some time and has been code driven, confusion remains as to what firestopping is all about. If you envision firestopping as a circle, there are three major influences acting upon that circle to ensure that effective firestopping is achieved:

Delivery — This influence encompasses the manufacturer, distributor and contractor. The key is to develop the most effective firestop products, place them in the distribution channel and install them.

Specification — This influence speaks to the high degree of knowledge required by the architect and/or specifier to ensure that the fire barriers are clearly defined and the best system is specified and applied.

Enforcement — This influence is vitally important in ensuring that the systems as specified and provided by the installer are, in fact, correct. The function of the inspecting code official or fire marshal should not be underestimated.

What is the common thread? Training. Training is a critical element for each influence mentioned above. Each of these influences, although they perform a distinct function, collectively work together to ensure that the proper firestop system has been installed. This team effort dramatically increases the probability that the firestop system will be effective in the event of a fire.

SYSTEM SELECTION

Today, system selection is a relatively easy task since most manufacturers of firestop materials provide design details of systems that were tested at a third-party testing agency. These systems will carry classification numbers, and these numbers should be plainly identified on any system drawings.

The following guide should be considered when selecting a firestop product to complete a system. (Note: this list is not all-inclusive):

The type of assembly — wall or floor, concrete (lightweight, normal, or hollow-core), drywall or masonry

The type of opening — round, rectangular or irregular

The type of penetrating item — pipe (metallic or non-metallic), insulated or uninsulated, cable or conduit, ductwork, electrical outlet box or receptacle

The type of firestop material to be applied — intumescent, endothermic, high temperature blanket

Selecting or installing a firestop material that will not perform within a system is a potential formula for disaster. For example, an “endothermic” product absorbs heat during a fire. Its function in life is to just take the heat, and typically this type of a product would be applied to a metallic pipe system that penetrates a fire rated barrier. As a metallic pipe is uninsulated, this would be a good selection.

If, however, an endothermic product is applied to an insulated pipe (fiberglass, elastomeric, etc.), the system will fail in an actual fire condition since the endothermic will not expand (intumesce) to fill the void left after the insulation is consumed in the fire. The end result is that smoke, gas, and potentially fire will migrate into the contiguous compartment.

The solution is easy — demand to see the “system” that the manufacturer has tested. Specify the system. Enforce the system. The systems available from manufacturers will cover a high number of penetrations that one would normally encounter in standard construction. Of course, there will be occurrences when a sledge hammer may be used to create an opening for a two-inch iron pipe — that is to say, the hole is too large for the penetrating item, or the penetration is not covered by a system drawing.

In those events, an engineered judgement can be issued from the manufacturer. An engineered judgement is designed to render an opinion (from the manufacturer’s engineering staff) for treating the unusual condition. This recommendation should be based on similar tested systems and referenced as such. Accepting the claim: “this ought to work”, without receiving a design detail based on the current conditions is dangerous. Engineered judgements should be used sparingly, but remember, they are typically a function of how the building really “goes up”, rather than how it was designed. Manufacturers can easily provide 30 to 100 engineered judgements per week — they are reliable, but should never be a substitute for a valid “system”.

THE TELECOMMUNICATIONS STORY

In earlier days, when telecommunications was an infant industry, firestopping was not the issue it is today. Many facets of our lives now require telecommunications, and the markets are growing daily.

Circuit integrity and equipment protections are paramount in maintaining the high levels of communication we require to perform the simplest tasks. As our communication systems sprawl through buildings, crossing fire rated walls and floors, the opportunity for a fire to spread through a building increases with each penetration
we create.

Each penetration through a wall or floor creates an egress for smoke, gas and flames if it is not treated. In most fires it is not the flames that necessarily kill — it is the smoke and toxic gases that are generated even before the flames erupt. In some fires, smoke and toxic gases kill people in areas that are not even engulfed in flames. Why? Because smoke and toxic gases will migrate through fire rated floors and walls if those penetrations are not properly sealed with quality firestop materials.

In the telecom world, as we poke and probe those walls and floors in the pursuit of establishing better communications, we need to consider both the impact of having the best telecom setup in the world and the protection of the people who will keep that system running smoothly. Firestopping in the telecommunications industry should be a forethought, and an integral part of the installed telecom system.

CODES AND REGULATIONS

In Canada and the United States, local codes are drawn and adapted from the national model building codes — codes such as the Basic National Building Code, published by the Building Officials and Code Administrators (BOCA) Inc.; the Uniform Building Code, published by the International Conference of Building Officials (ICBO); and the Standard Building Code, published by the Southern Building Code Congress International (SBCCI). Local codes in many cities are frequently based on one of the national codes, and state fire marshals and local fire departments may also have specific fire code requirements to be reviewed. Canadian fire protection codes parallel those of the United States, and Underwriters Laboratories of Canada (cUL) is one of the primary testing agencies for the Canadian market.

Any agency or authority having jurisdiction should be checked by the architect, engineer, or design specifier before final plans are drawn for fire-resistive requirements and fire ratings of walls and floors.

Each model code contains specific language that addresses fire-resistant construction. This information is typically found in the mechanical codes that provide details on how this construction is to be carried out. The mandate for the plans, specifications and responsibilities of the code official are typically found in the administrative section.

Firestopping is serious business. Effective firestopping is achieved through testing, training, conscientious specification and knowledgeable enforcement.

Firestops are an integral part of any fully-implemented containment system and they complement the active components of building fire protection. Firestopping provides life safety and equipment protection — it is that simple.CS

Robert C. Gram joined Nelson Firestop Products, Tulsa, OK, in 1998 and is currently Director of International Sales and Marketing at the company. Prior to joining Nelson, he worked in the commercial and industrial insulation market in both distribution and manufacturing for over 18 years.


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