|
Roof
Insulations |
|
|
9.5 Installation Considerations
9.5.1 Protection from Weather. Insulation should not be left
exposed to the weather. No more insulation should be applied
than can be completely covered with the finished membrane on
the same day.
JM roof insulations are shipped covered with plastic shrouds
which are intended to temporarily protect the material while in
transit. All roofing materials should be stored on the jobsite with
a weatherproof covering such as a tarpaulin. Factory
packaging should not be relied upon as protection from the
weather.
9.5.2 Asphalt Temperatures. JM endorses the guidelines
established by the NRCA and ARMA for heating asphalt for
proper insulation applications. Asphalt should be applied at the
Equiviscous Temperature (EVT), ± 25°F (±14°C).
9.5.3 Cold Weather Application. Hot asphalt chills rapidly at
40°F (4°C). To avoid problems associated with "cold" asphalt
application, insulation should be applied with mechanical
fasteners or the "mop and flop" method of installing insulation.
The "mop and flop" method entails mopping the back of the
insulation so that the asphalt retains its adhesive qualities for a
longer period. When applying insulation with hot asphalt, board
size should not exceed 4' x 4' (1.22 m x 1.22 m). Care should
be taken in any application below 40°F (4°C).
9.5.4 Mechanical Application to Steel Decks. Mechanical
attachment of insulation to steel decks is the only acceptable
attachment method. For current information regarding Factory
Mutual requirements over insulated steel decks, please check
with a JM Technical Service Specialist, or the current FM
Approval Guide.
9.5.5 Cold Adhesive Application. JM insulations may be
installed in MBR® Cold Application Adhesive. For additional
installation information, refer to Section II, Insulation
Specifications.
9.5.6 Foam Insulation Products are Combustible. They
should be properly protected from exposure to fire during
storage, transit and application.
9.5.7 Mopping Asphaltic Membranes to Foam Insulations.
Although Fesco Foam and E’NRG’Y 2 are compatible with
hot asphalt and asphaltic membranes, JM supports PIMA and
NRCA in recommending that a cover board of Fesco Board,
Fiber Glass Roof Insulation or ½" Retro-Fit Board be installed
over foam insulations.
9.5.8 Limitations. When installed over metal decks, spans
shall be limited for specific deck gauges as outlined in the
current FM Loss Prevention Data Sheets 1-28, 1-29 and
Factory Mutual Approval Guide. JM insulations are not
recommended for applications where temperatures are
maintained in excess of 200°F (93°C). Although JM roof
insulations are designed to be compatible with most
membranes, the membrane manufacturer should be consulted
for specific approval with individual membrane products.
9.6 Foam Thermal Values
9.6.1 Thermal Values. The thermal values of all closed cell
urethane or isocyanurate foam insulations are at their optimum
at the time of manufacture. As these products "age", some
thermal loss occurs due to air infiltrating the foam cells and
diluting the insulating gas in the cells. This process continues to
occur over time. The degree to which this occurs is a function
of the product formula and quality. It may vary from one
manufacturer to another. The ultimate R-value of foam products
will also depend on individual installation circumstances.
9.6.2 Conditioned R-Value. JM Fesco Foam and E’NRG’Y
2 roof insulations are sold based on 6-month conditioned
thermal values as determined by the PIMA Thermal
Conditioning Procedure. JM has elected to support the use of
the PIMA 6-month conditioning procedure because it is the only
standard currently available in the roofing industry. The use of
6-month conditioned thermal values by architects and
specifiers should be done with the knowledge that the
isocyanurate foam insulation products will continue to age
beyond the published values. No manufacturer or organization
has been able to identify the thermal value that urethane or
isocyanurate foam insulation will reach in a roofing system after
years of service. Continuing research is being undertaken, and
JM supports this activity for the benefit of the roofing industry.
9.6.3 Design R-Value. When calculating the anticipated
thermal performance over the expected life of
isocyanurate foam insulation products, JM suggests the
use of an R-value of 5.56 per inch of foam thickness (0.98
m2 • °C/W).
9.6.4 PIMA Thermal Conditioning Procedure. These
guidelines were published in PIMA Technical Bulletin No. 101.
They were endorsed by the National Roofing Contractors
Association (NRCA) and adopted by many state and local
code authorities. They are also included in Federal
Specification HH-I-1972 and ASTM C 1289.
9.7 Definition of Terms and Symbols
9.7.1 k-Value (Thermal Conductivity): the measurement of
heat flow in BTUs through a 1" (25 mm) thickness of any single
homogeneous material, per hour per sq. ft. per degree F
temperature difference (W/m • °C).
9.7.2 C-Value (Thermal Conductance): the measurement of
heat flow in BTUs per hour per sq. ft. per degree F temperature
difference through any single material, regardless of thickness
(W/m2 •°C).
9.7.3 R-Value (Thermal Resistance): the measurement of
the resistance to heat flow. The reciprocal of the C-value.
9.7.4 U-Value (Overall Heat Transfer Coefficient): the
measurement, in BTUs of heat flow, per hour per sq. ft. per
degree F temperature difference through a combination of
materials such as roof deck, vapor barrier, roof insulation,
built-up roofing, and the air films below and above such
combinations.
