FAQ's

This page is offered as a presentation of questions specific to the art of firestopping and the needs of the firestopping professional.

SUBMIT A QUESTION

Q:

WHAT IS FIRESTOP?

A:

Firestopping has a complicated definition. However, there are two key words to remember when discussing firestopping.

A through penetration is simply a hole that has been made in a fire rated barrier in order to run cables, pipes, tubing, etc.

A firestop system is simply a patching method used to seal that hole and restore the fire-rating.

Q:

WHAT DO I NEED TO KNOW ABOUT FIRESTOPPING IN ORDER TO MAKE GOOD DECISIONS?

A:

If you are a specifier, you need to know what products and systems best suit your application.

If you are a contractor, you should have these same concerns before you think of price.

If you are an inspector, your concerns will be "did the specifier make the right choices and did the contractor do the job correctly?"

Q:

WHAT SHOULD I ASK IN ORDER TO DETERMINE THE RIGHT SYSTEM?

A:

1. What type of construction am I dealing with?
2. What is the hourly rating?
3. What is the barrier made of and how is it made? gypsum board? masonry? concrete block?
4. How big is the opening?
5. How big is the annular space around the penetrants?
6. What type of penetrants am I dealing with? conduits? metallic or non-metallic? how many? how big? pipes? are they vented or unvented? cables? what type? how many?
7. Are there any special considerations in this particular application?
8. Will pipes move or vibrate?
9. Is there any unusual expansion and contraction?
10. Will there be a need to modify the penetrants frequently?

Q:

HOW DO I KNOW IF I HAVE CHOSEN THE RIGHT SYSTEM?

A:

This is a difficult question to answer. Specifiers, installers, and inspectors need to familiarize themselves with commonly used products. The best source for information is the manufacturers themselves. Additional information can be found in the UL Fire Resistance Directory (beginning with 1990 directory). It is important to understand, however, that the UL systems show the limitations to the test and not necessarily the limitations of the products. Get to know the limitations of the products. Ask manufacturers for guidelines on the use of products.

What limitations are there in way of annular space requirements, depth of material used, limits on size, number, and material of penetrants. Everyone is conscious of liability these days. Reputable manufacturers are generally pretty honest about the limitations of their products. When in doubt ... ask for help. The manufacturers of firestop products have performed more fire tests than anyone else. When you have a question, take advantage of their knowledge and experience.

Q:

WHAT DO THE TERMS "INTUMESCENT," "ENDOTHERMIC," AND "ELASTOMERIC" MEAN?

A:

"Intumescent" means that material expands when exposed to fire or heat to fill a void in the penetration caused by the deformation or combustion of the penetration item. An "endothermic" product blocks heat by chemical absorption and moisture release. "Elastomeric" products are flexible and prevent passage of heat and gasses while permitting movement of the assembly.

Q:

CAN I USE OTHER COMBUSTIBLE MATERIALS WITHIN A FIREWALL OR FIRE SEPARATION?

A:

NO. Most codes deal with this by stating that any material that is going to be used within a firewall or horizontal fire separation must be tested within the original firewall or separation at the time of testing.

Q:

WHAT DO THE RATINGS "T," "F," AND "L" MEAN?

A:

A "T" rating indicates the amount of time (usually hours) it takes the temperature on the non-fire side of a fire-rated assembly to exceed 325 degrees Fahrenheit above ambient temperature. An "F" rating indicates the amount of time (hours) that a fire-resistive barrier can withstand fire before allowing flame to pass through an opening. An "L" rating denotes the amount of air leakage (cubic feet per minute) through a penetration.

Q:

DOES AN "F" RATING (FIRE) WITHOUT AN "FT" RATING (FIRE AND TEMPERATURE) MAKE A FIRESTOP SYSTEM ACCEPTABLE?

A:

North American Building Codes generally state that all firestop assemblies penetrating a firewall or horizontal fire separation, in order to meet code, must have an "FT" rating not less than the fire-resistance rating for the fire separation.

If a firestop system has an "F" rating of 2 hours and a "T" rating of 15 minutes, this assembly has an "FT" rating of 15 minutes ... not 2 hours. The "F" and "T" ratings are not separable. The ratings are expressed as the lowest of both the "F" and "T" ratings.

Q:

IF BOTH SIDES OF THE WALL ARE SPRINKLERED, DO I HAVE TO FIRESTOP?

A:

Yes, because sprinklers do not address the passage of smoke and gases. Firestops do. In actual building fires, the majority of deaths (over 75%) are caused by smoke and not fire. Both the UBC and NBC require the containment of not only fire, but also gases and smoke.

Q:

WHAT IS THE DIFFERENCE BETWEEN A FIRE SEPARATION AND A FIREWALL?

A:

A fire separation is a construction assembly that acts as a barrier against the spread of fire. A fire wall is a type of separation that subdivides a building or separates adjoining buildings.

Q:

WHAT ARE APPROVED METHODS?

A:

"Approved methods" is a general term that refers to firestop systems that have been tested by an independent laboratory (e.g., Underwriters Laboratory) and which meet ASTM E 814 performance criteria.

Q:

WHAT ARE ENGINEERED JUDGEMENTS?

A:

They are recommendations system/product manufacturers sometimes make to meet actual field conditions, based on testing that approximates the conditions encountered.