 |
FCIA Standard Answers to Common Questions
Document 1 - Equal F & T Ratings
FCIA Firestop Contractor Members report that Specifications sometimes
request equal F and T Ratings on metallic and other penetrating
items, joints and gaps with no extra treatment specified by the
architect. The purpose of this "Standard Answers" paper
is to provide clarification for FCIA Member Contractors and the
construction industry about "Equal F and T Ratings" for
Firestopping
Definitions - Firestop Systems tested to ASTM E 814 or UL 1479
result in hourly ratings for both flame ("F") and temperature
transfer ("T"). The "F" Rating defines the amount
of time before flame pokes through openings to the unexposed side
of the test assembly. The "T" Rating defines the amount
of time for the surface of the penetrating item on the non-fire
side of the test assembly to rise 250F plus ambient temperature.
The purpose of the "T" Rating is to prevent fire spread
from the fire side to the non - fire side of the assembly even when
no breach in the fire resistance rated compartment exists that would
allow flame propagation. Below is discussion regarding the "Equal
F and T Ratings" issue that affects FCIA Member Specialty Firestop
Contractors regularly:
The 2000 edition of the International Building Code requires equal
"F" and "T" Ratings for items penetrating through
fire resistance rated floor assemblies. In floor assemblies, penetrations
contained and located within the cavity of the wall do not require
a "T" Rating. For floor penetrations outside wall cavities,
"T" ratings of no less than 1 hour or the required rating
of the floor penetrated are. When penetrations are in fire resistance
rated walls, there is no mention of a "T" rating requirement.
(See IBC 2000 Code for further explanation)
Upon review of the 2004 Underwriters Laboratories, (UL) Fire Resistance
Directory for through penetration firestop systems, FCIA Member
contractors found the following results:
- Metal Pipe Testing - In the CAJ, CBJ, FA, WJ, metallic penetrating
item series tested systems in concrete floors, concrete and concrete
block walls, there are no listed systems with equal "F"
and "T" Ratings. In some cases, a "T" Rating
of ¼ to 1 hour can be attained in WJ (Walls) systems depending
on the system requirements. Insulation may be required to be wrapped
around the penetrating item, 2" thick, extended 12"
past the fire resistance rated assembly on both sides of the wall/floor,
in concrete assembly to attain the "T" ratings equal
to the "F" Ratings. For wood framed assemblies, there
are some cases where equal "F" and "T" Ratings
exist. The ratings are available on mainly pipe diameters of 4"
and less.
- Plastic Pipe Testing - The CAJ 2000 series plastic pipe assemblies
have a significant number of tests where equal "F" and
"T" Ratings occur. However, there are a number of tested
plastic pipe, through penetration firestop systems where the "T"
Rating is less than the "F" Rating.
Additionally, whenever a metallic sleeve is used in the penetration
assembly, the "T" Rating is reduced to "0"
hours.
- Insulated Pipe Testing - In cases where metal plumbing, or
electrical piping is covered continuously with insulation, ratings
with "F" and "T" Ratings either less than
or equal to each other are available in testing directories. Insulation
can either be continuous or partial to attain these "T"
Ratings.
For insulated metal piping, where insulation is not continuous,
there are tested systems available. Typically, approx. 36"
of insulation, of approx. 1 - 3" thickness, depending on
the system, installed so that 12" plus extensions above and
below the fire resistance rated assembly is applied to attain
a "T" Rating. Consult specific tested and listed systems
for details.
When electrical conduit is insulated to attain a "T"
Rating, particular attention must be paid to the thickness of
insulation applied and it's affect on ampacity capacities. Insulation
may "derate" ampacity capabilities, limiting power transmitted,
and possibly creating a fire hazard.
- Cable Testing - Although there is metal used in cable assemblies
for wire, conduit, etc., there are some rated systems where equal
"F" and "T" Ratings exist. Where aluminum
piping is used, "T" Ratings will be higher than harder
metals due to the low melt point of aluminum, meaning the pipe
will melt before it has a chance to transfer temperature to the
non-fire side of the assembly.
- Joints and Gaps - All tested and listed assemblies are available
with equal "F" and "T" ratings in joint assemblies
as the test criteria requires an equal "F" and "T".
In cases where non "insulated" firestop systems are
used, "F" ratings may be greater than "T"
Ratings. "T" Ratings may be as low as "0"
hours.
Based on the above referenced information, it is FCIA's position
that "Equal "F" and "T" Ratings can be
provided in some cases. However, Equal "F" and "T"
Ratings may not be available in all cases. Architects and engineers
shall communicate the need for equal "F" and "T"
ratings when required by code for life safety or property protection
in construction documents, with specific tested and listed systems
referenced to accomplish the ratings.
Due to the limited number of available tested and listed systems
in metal pipe applications, there may be engineering judgments or
equivalent fire resistance rated assemblies (EJ's or EFFRA's) needed
to provide the specific "T" Ratings ratings requested.
FCIA Standard Answer # 1 - "Equal "F" and "T"
Ratings May 6, 2004 FINAL DRAFT
Firestop Contractors International Association
FCIA Technical Committee Document number 1
4415 W. Harrison St.
Hillside, IL 60162
Phone: (708) 202-1108
Fax: (708) 449-0837
info@fcia.org - Email
Read the article in MS Word format
|
