introduction to fireblock and firestop sealant systems.
A concrete wall floor assembly being inserted into the furnace.
Firestop and fireblock sealants have two commonalities: they
both contain the word “fire” and are both an integral part of life safety. When
a fire occurs, smoke and fire can spread quickly. The amount of time it takes
to spread depends on structural openings, which feed the fire with oxygen and
allow it to travel from room to room and floor to floor. Firestop or fireblock
sealants allow responders to rescue occupants and extinguish the fire with the
least amount of damage.
A structure is made up of floors, walls and ceilings. At intersections where
they meet, there are voids or joints. Filling joints with a firestop or
fireblock sealant will help create a “compartment.” In one-room structures, the
fire will be sealed within the room - no outside air will fuel the fire and
there are no joints for the fire to escape until the walls, floor, and ceiling
are compromised. In the case of multiple-room structures, the goal is
compartmentalization - to contain the fire in the room in which it originated
for as long as possible.
After the floors, walls and ceilings are constructed, pipes, wires, cables,
ducts, and other components can be installed. Unfortunately, when a hole is cut
it is not the exact size of the penetrating item to be installed, which results
in an annular space. This space, which can give a fire momentum, must be
filled. A firestop or fireblock sealant can be used to prevent the passage of
flame and smoke. It can also restrict the flow of oxygen from one compartment
to the next.
A look inside the furnace while a test is being performed.
Fireblock sealants are for use in one- and two-family dwellings
and are covered in the International Residential Code (IRC):
Fireblocking shall be provided to cut off all concealed draft
openings (both vertical and horizontal) and to form an effective fire barrier
between stories, and between a top story and the roof space. Fireblocking shall
be provided in wood-frame construction in concealed spaces of stud walls and
partitions; vertically at the ceiling and floor levels; and horizontally at
intervals not exceeding 10 feet. Install fireblocking at openings around vents,
pipes, ducts, cables, and wires at ceiling and floor level with an approved
material to resist the free passage of flame and products of combustion.
Over the years, the definition of a fireblock has evolved in the IRC.
Originally, a fireblock was defined as a non-combustible sealant that was
tested to and passed ASTM E 136, “Standard Test Method for Behavior of
Materials in a Vertical Tube Furnace at 750°C.” This definition has since
changed; no longer is compliance with ASTM E 136 a requirement.
Choosing the right fireblock sealant can be confusing. The Authority Having
Jurisdiction (AHJ) that inspects the proper installation of the fireblock
sealant may use one of many building codes. The regional building codes used in
the past are being replaced with the IRC. But, depending on the AHJ, any one of
many building codes could be used. If the AHJ references the IRC, the proper
fireblock sealant can vary, depending on what year’s version of the IRC is
Hose stream test.
Installation and Inspection of Fireblock Sealants
Installing a fireblock sealant and receiving approval from a
local inspector can be tricky. A contractor can install fireblock sealants in a
home and receive an approval by a local inspector, then install the same
sealant in a location five miles away and fail inspection.
In addition, some inspectors allow the use of expanding foams for fireblocking.
Contractors appreciate the labor savings of these foams - a quick push of the
finger and the annular space is sealed. However, many inspectors will not allow
the use of foam because it burns so quickly and expels toxic gases in the event
of a fire. Even if the inspector is using a code that does not require the use
of a non-combustible fireblocking, he or she may not allow it to be used. What’s
more, some inspectors require that the fireblocking material be red in color,
even though there are non-combustible fireblock sealants in other colors.
The more knowledgeable the inspector is in the codes and what to look for in a
fireblock sealant, the easier it is on the contractor applying the material.
The contractor’s know-how is also an important factor; familiarity with the
codes and the local inspector’s fireblock requirement is a must. While there
are many different codes, there is one constant throughout all jurisdictions:
Application of a non-combustible fireblock sealant will always be approved if
installed properly. Proper installation means completely sealing the opening.
Firestop sealant applied to penetration.
There are three key elements to life safety: detection (fire
and smoke alarms to warn of the problem); suppression (sprinklers, fire
extinguishers, etc., to help keep the fire at bay); and compartmentalization
(to keep the fire isolated, as described previously). Detection alone is
obviously not a good option; in a high-rise building, detection without
suppression and compartmentalization may result in lives lost. Suppression
alone means that the fire can travel within walls and floors very quickly - two
places where sprinklers are ineffective. In addition, improper maintenance of a
sprinkler system can render it useless. If the building is compartmentalized,
occupants may have time to safely evacuate in the event other systems
malfunction. Even if properly working sprinklers suppress the fire, the
building will still be full of smoke. Smoke inhalation is the cause of 75% of
fire-related deaths. If the building is properly compartmentalized, the smoke
will be isolated, providing occupants with more time to escape safely.
Firestopping is also known as passive fire protection - the sealing and
compartmentalizing of rooms between fire-rated walls, floors, and ceilings.
These fire-rated assemblies are found in commercial construction. Fireblock
sealants are used in non-fire-rated walls, floors and ceilings. Remember that
they are used in Type V combustible construction, which is commonly found in
residential construction. A fireblock sealant is used alone to seal openings. A
firestop sealant is used in conjunction with other building materials as a
Application of firestop sealant.
Firestop Codes and Testing
Firestopping is addressed in the National Building Code
(NBC), Uniform Building Code (UBC), Standard Building Code (SBC), NFPA 101 Life
Safety Code, NFPA 70 National Electrical Code, Uniform Plumbing Code (UPC) and
the International Building Code (IBC). The IBC states:
Through penetrations shall be protected by an approved penetration
firestop system installed as tested in accordance with ASTM E 814/UL 1479
(Standard Test Method for Fire Tests of Through Penetration Firestops). An
F-Rating of not less than the required fire resistance rating of the wall
penetrated. An F-Rating and T-Rating of not less than the required rating of
the floor penetrated. Joints installed in or between fire resistant rated
assemblies shall be protected by an approved fire resistant joint system
designed to resist the passage of fire for a time period not less than the
required fire resistance rating of the assembly in which it is installed. Fire
resistance joint systems shall be tested in accordance with the requirements of
ASTM E 1966/U.L. 2079 (Standard Test Method for Fire Resistance of Building
Unlike fireblock codes, firestop codes are very specific and have no room for
interpretation by the AHJ. Walls, floors or ceilings in a building are tested
in a fire for 1, 2, 3 and 4 hours per ASTM E 119/UL 263 (Standard Test Method
for Fire Tests of Building Construction and Materials) and thus rated for 1, 2,
3, or 4 hours. These tests are performed by the following third-party testing
laboratories: Underwriter Laboratories Inc. (UL); FM Global (Factory Mutual);
Intertek (Warnock Hersey, Omega Point Laboratories); and Southwest Research
Institute. These labs test to American Society of Testing Materials (ASTM) and
Underwriter Laboratories Inc.
There are three parts to a firestop system: a fire-rated wall, floor or
ceiling; a penetrating item; and the firestop fill material. The testing of the
system consists of duplicating the construction of the wall or floor; cutting
holes and installing penetrating items; and filling the annular space with
firestop sealant. In many cases, mineral wool or a backer rod is also part of
the firestop fill material. After the wall or floor is constructed, the
dimensions of all components are recorded: the thickness and material
(concrete, wood joists, gypsum board) of the wall or floor; the size of the
penetrating item (such as 2” PVC pipe, 4” copper pipe, 24” x 24” duct, or 2” x
2” bundles of wires or cable); the size of the hole cut for the penetrating
item; the annular space remaining, which is filled with firestop sealant; and
the thickness of the mineral wool or size of the backer rod in the annular
space and the thickness of the firestop sealant applied.
This duplicate assembly is then placed in a furnace and burned for 1, 2, 3 or 4
hours at temperatures from 1,600°F for one hour up to 2,000°F for four hours.
At the end of the burn, the floor or wall is removed from the furnace, stood on
its side and subjected to a hose stream of 30 psi. The amount of time exposed
to the hose stream depends on the size of the assembly. If the unexposed side
of the penetration or opening is intact with no water or holes observed after
the hose stream test, that assembly has passed.
During the test, the following fire-resistance ratings are recorded.
- F-Rating - The time period that the
firestop system resisted the spread of flame through the penetration or
opening. If the assembly was tested for two hours and no flame spread out of
the furnace through the penetration, a two-hour F-Rating has been
- T-Rating - The time period that the
firestop system resists the passage of flame through the penetration or opening
and limits the maximum temperature rise on the unexposed side to less that
325°F above ambient temperature. If the assembly was tested for two hours, but
the penetrating item temperature rose 325°F above ambient temperature after one
hour, a one-hour T-Rating has been achieved.
- L-Rating - The time period that the
firestop system limits the spread of smoke through the penetration or
This data is written up into a “system” if the tested assembly was successful.
The system is proof that the particular assembly, with all the specific
penetrating item dimensions and firestop fill material thicknesses, passed the
test for 1, 2, 3, or 4 hours. Keep in mind that there are thousands of tested
systems to cover all of the possible combinations of wall, floor, and ceiling
assemblies, as well as various diameters and types of pipes, cables, wires, and
ducts. This testing is necessary to ensure that if a building is constructed of
two-hour fire-rated assemblies and the assemblies have been compromised by the
additions of penetrating items, those assemblies will be brought back up to a
Installation and Inspection of Firestop Sealants
Firestop sealant installers should ensure that the sealant
they are using has been tested to the systems in which it will be installed.
The system should be installed exactly as written up - which is how it was
tested. In addition, installers must be aware of the F and T Rating required
for that construction.
After installation, an AHJ will visit the job site for an inspection. The
installer presents the inspector with the systems that were installed and the
inspector ensures that all assemblies and penetrating item dimensions match up.
He or she will randomly disassemble a system to ensure the correct amount of
mineral wool or backer rod has been used and the correct depth of firestop
sealant has been applied.
The knowledge level of firestop sealant installers varies. Individual
tradespeople (such as plumbers, electricians, HVAC, etc.) may perform the
installation; in many cases, these installers are given a caulk gun and a case
of firestop sealant and are told to seal around all the holes. Sealing around
the holes, however, is generally not the same as installing a system. An
improperly trained inspector may look at this type of installation, see red
sealant applied, and approve the installation. However, this is not the intent
of the codes and will not properly compartmentalize a building.
Fortunately, there are firestop contractors available with professionally
trained installers. The Firestop Contractors International Association (FCIA)
has members throughout the world that can perform the proper installation of a
firestop system. A list of contractors can be found on www.fcia.org. In
addition, Underwriters Laboratories Inc. (www.ul.com
) and FM Global (www.fmglobal.com
) have firestop contractor
programs available to ensure proper training.
An inspection by a properly trained and knowledgeable AHJ will enforce codes
and ensure the proper installation of firestop systems. The International
Firestop Council (IFC), a not-for-profit association of manufacturers,
distributors and installers of passive fire-protection materials and systems,
offers free training seminars for inspectors throughout North
For more information about firestop materials and the IFC, visit www.firestop.org.