What is Perlite?
Thermal Design- Concrete Masonry
Thermal Resistance Calculations
Perlite Masonry Block Loose-Fill
Perlite Loose-Fill Insulation
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Perlite Loose-Fill Insulation
Perlite loose fill insulation is an inert volcanic glass expanded by a special heat
process that can be treated with water repellent material when necessary. The resulting
granular product is lightweight with countless tiny, sealed air cells, which account for
its excellent thermal performance and fire resistance.
Perlite insulation has been proven over a period of many years in the insulation of
storage tanks for liquid gases at temperatures as low as 400 degrees Fahrenheit (-240
PROPERTIES AND BENEFITS:
Insulating--Reductions in heat transmission of masonry walls of 50% or more may be
obtained with perlite loose-fill insulation. Thermal performance tests using ASTM
C236, Test Method for Steady State Performance of Building Assemblies by Means of a
Guarded Hot Box have shown perlite to be a superior concrete block insulation when
compared to vermiculite, EPS inserts, EPS beads, and foamed-in-place insulation's.
Recent testing of an 8 inch medium weight concrete block wall filled with perlite
loose-fill insulation using dynamic conditions simulated by a National Bureau of Standards
24 hour (diurnal) test cycle indicates that the measured total energy (total heat flow
through a wall for a 24 hour period) was only 72 percent of the total energy predicted by
Non-Combustible--The fusion point of perlite is 2300 degrees Fahrenheit
ASTM E84--Flame Spread 0, Fuel Contribution 0, Smoke Density 0.
Fed.Spec.HH-1-515D--Critical Radiant Flux greater than 1.07 Watts/cm2. Smoldering Combustion, Flaming Combustion - None,
4 Hour Fire Ratings--Underwriters' Laboratories Design No. U905 shows
that a 2 hour rated 8, 10, 12 inch (20, 25, or 30 cm) concrete block wall is improved to
four hours when cores are filled with water repellent treated perlite. U.L. Designs
U901, U904, and U907 also achieve 4 hour fire ratings.
Permanent--Perlite is an inorganic, naturally occurring mineral and it is
as permanent as the walls which contain it. It supports its own weight and will not
settle or bridge.
Water Repellent--Perlite loose fill insulation can be treated to minimize water
transmission. Laboratory tests on water transmission by Structural Clay Products Research
Foundation showed a cavity wall filled with treated perlite resists transmission of water
to the interior wythe even under the most severe conditions. Performance of overall wall
was rated "excellent" in accordance with procedures established by the National
Bureau of Standards in BMS 82. However, it should be noted that treated perlite insulation
will not waterproof a poorly constructed masonry wall. Good construction practice
should also incorporate the use of weep holes covered with copper, galvanized steel, or
Sound Reduction--Perlite loose fill insulation has the ability to fill all voids,
mortar lines, and ear holes thus enabling it to reduce airborne sound transmission through
walls. Lightweight 8 inch (20 cm) masonry block filled with perlite achieves an STC of
approximately 51 which exceeds HUD sound transmission standards.
Economical--Perlite loose-fill masonry insulation offers excellent thermal and fire
resistant properties at an economical cost. It is lightweight and pours easily and
quickly without requiring special equipment or skills.
STANDARDS, SPECIFICATIONS AND REFERENCES
- ASTM Specification C549 for Perlite Loose Fill Insulation
- ASTM Specification C520 Density of Granular Loose
- ASTM Specification C236 Test Method for
- Performance of Building Assemblies by Means of a
Guarded Hot Box
- ASTM Specification E84 Test for Surface Burning
Characteristics of Building Materials
- FHA Use of Materials Bulletin UM-37
- GSA Commercial Item Description A-A-903 Insulation,
- Brick Institute of America Technical Notes No 21A
- Federal Specification HH-I-515D