CIMA Technical Bulletin #1
A comprehensive body of federal regulations, government and private
procurement specifications, building code requirements, and effective,
time-proven voluntary industry standards makes cellulose insulation
a building material you can buy, specify, and install with confidence.
Cellulose building thermal insulation is a recycled product made from
recovered newsprint, the largest single component of the residential
waste stream in most communities.
Dry loose-fill cellulose insulation is installed in attics and walls with
pneumatic blowing machines. Existing walls may be insulated by blowing
insulation in through access holes. The holes may be at the top, bottom,
and either inside or outside the building. A variety of methods are used
to insulate new walls with dry cellulose. Techniques include using jigs
or forms to fill open face cavities prior to installation of sheetrock.
Various types of permanent retainers are also used in walls, crawl spaces,
or cathedral ceilings.
Cellulose insulation spray-applied in wet form is a self-supporting
material. It relies on water, adhesive, or a combination of both to build
bond strength to a substrate and within itself. Spray-on products may be
used in wall cavities (fully open and dried before covering) or on other
suitable exposed wall or overhead surfaces.
Confusion over standards
Architects, specifiers, inspectors, contractors, buyers, and occasionally
even manufacturers are sometimes unsure about the laws, regulations,
specifications, and standards that apply to cellulose building insulation.
Cellulose insulation has grown in acceptance since it was first identified
generically in General Services Administration Standard HH-I-5 15. It has
been exposed to a broad range of construction, environmental, and various
code requirements that called for more elaboration and definition of physical
properties. These requirements have been identified and met in the following
federal regulations, federal procurement specifications, and industry standards.
- 16 CFR Part 1209:
- (The CPSC Safety Standard) 16 CFR Part 460 (The FTC R-Value Rule)
- ASTM C-739:
- Standard Specification for Cellulosic Fiber [Wood-Base] Loose-Fill Thermal insulation)
- ASTM C-1149:
- (Standard Specification for Self-Supported Spray Applied Cellulosic Thermal/Acoustical Insulation)
- HH-I-515E:
- (The General Services Administration purchasing specification for
loose-fill cellulose insulation requires ASTM C-739 conformance.)
The states of California and Minnesota have their own insulation regulations
which are based on the ASTM Standards and, in the case of cellulose insulation,
on the CPSC standard. Of course, the insulation requirements of all building
codes also apply to cellulose.
Standards, specifications, and test methods that are not currently applicable
to cellulose insulation include:
- The Two-Foot Tunnel Test
(Not used for over 10 years, when it was determined to be inadequate.)
- The Basket Test
(Not used for over 10 years, when it was determined to be inadequate.)
- ASTM E-84
(The tunnel flame spread test is no longer used to assess the
surface burning characteristics of loose-fill cellulose insulation. In the 1970s
it was replaced in ASTM C-739 and the CPSC standard by the radiant panel test
[ASTM E-970], which is regarded as more appropriate for loose-fill insulation.
The E-84 flame spread test applies only to cellulose fiber when used as a
spray-applied self-supporting material where the surface remains exposed in
a vertical or overhead mode.)
"Good enough" isn't good enough!
The minimum legal requirement for cellulose insulation is the CPSC standard,
which covers four product attributes, critical radiant flux, smoldering
combustion, corrosiveness, and settled density.
The CPSC standard adequately addresses safety issues, but safety -- important
as it is -- is only one factor in insulation performance. The standard for
loose-fill cellulose insulation accepted by the insulation industry is ASTM
C-739, which provides tests for R-value, odor, moisture vapor sorption, and
fungi resistance, as well as critical radiant flux, smoldering combustion,
corrosiveness, and settled density, the attributes covered by CPSC standard.
In addition to omitting four material characteristics that are not
safety-related, the CPSC standard has not been amended since 1978.
Accordingly, it does not reflect changes that have occurred since
then. Most notable of these changes is widespread use of compressive
packaging. To compensate for this, ASTM C-739 added a pre-blow step
to the settled density test procedure to more closely reflect actual
installation procedures. Other than this 16 CFR Part 1209 and C-739
are essentially identical in the test procedures for their four common
material characteristics.
In 1990 the Federal Trade Commission endorsed the ASTM methodology by
amending the R-Value Rule (16 CFR Part 460) to remove references to the
CPSC procedure and specify that enforcement will be based on the C-739 procedure.
In specification HH-I-5 1 5E the General Services Administration replaced detailed
testing and product attribute descriptions that were contained in the preceding
"D" specification with references to ASTM C-739. Military construction
specifications, including those published by the Defense Logistics Agency and
The Naval Facilities Engineering Command (NAVFAC) NA VFAC Guide Specification
NFGS 07216., reference ASTM C-739.
Although there is not necessarily considered to be a consistent direct
relationship, cellulose insulation conforming to ASTM C-739 would also be
expected to:
- Meet the requirements of 16 CFR Part 1209
- Qualify as Class I material under ASTM E-84
Cellulose insulation manufacturers are entitled to claim compliance with 16
CFR Part 1209 on the basis of compliance with ASTM C-739 and C-1149. This
authority is clearly stated in 16 CFR Part 1209.33(b), which says, in part:
“A reasonable testing program may include either the tests prescribed by the
standard, or any other reasonable test procedures.” Since the C-739 procedures
are obviously “reasonable,” cellulose that complies with C-739 is by definition
in compliance with 16 CFR Part 1209, unless CPSC proves it isn’t. It’s doubtful
CPSC would question any cellulose producer that can document C-739 compliance.
Building codes are required by the Consumer Products Safety Act to follow
the CPSC standard. Thus, cellulose insulation conforming with the federal
standard is approved for installation in any code jurisdiction.
Spray-applied cellulose
Cellulose insulation formulated and labeled as self-supporting,
spray-applied material is legally required to conform with the CPSC
safety standard for loose-fill cellulose. The CPSC procedures assure
the safety of this type of cellulose insulation, but do not address
all the important characteristics of the material as installed. ASTM
C-1149 is a more appropriate material standard.
Although many of the tests described in C-1149 differ from those in C-739
and the similar CPSC 16 CFR Part 1209 procedures, manufacturers are
justified in claiming CPSC compliance on the basis of the C-1149
methodology since the tests described in C-1149 are “reasonable test
procedures.”
ASTM C-1149 covers 10 material attributes: Density, thermal resistance,
surface burning characteristics, adhesive/cohesive strength, smoldering
combustion, fungi resistance, corrosion, moisture vapor absorption, odor,
and flame resistance permanency. Material installed using liquid adhesive
(Type I) also has substrate deflection and air erosion characteristic
requirements. Obviously, under C-1149 spray-applied material is tested
in the sprayed state.
Spray-applied cellulose installed in closed walls and in attics is approved
for use in every code jurisdiction on the basis of conformance with the
CPSC standard. Exposed spray-applied cellulose insulation may be subject
to the interior finish requirements of the building codes. Cellulose
insulation conforming with ASTM C-1149 qualifies as a Class I or Class A
interior finish as defined by all model building codes.
Stabilized cellulose
A relatively new form of cellulose is used in typically loose-fill
applications, but is generally considered to be a spray product. This
material is sometimes referred to as “stabilized cellulose,” although
that term remains unofficial. It uses adhesive, which is activated by
a small amount of water, to limit settling. It’s normally used in attics,
but may also be installed in walls, if it meets the performance requirements
defined for Type II material by ASTM C-1149.
Like all cellulose insulation products, stabilized cellulose must conform
with the CPSC safety standard. ASTM is currently developing a material
standard for stabilized cellulose. Until this standard is approved and
published the safety of stabilized cellulose is assured by conformance
with the requirements of CPSC. The requirements for Type III material
defined by ASTM C-1149 cover some attributes of stabilized cellulose.
Specifiers may wish to require conformance with this standard.
Installation standards & practices
Loose-fill cellulose insulation, like all loose-fill insulation, should
be installed in accordance with ASTM Standard C-1015, Standard Practice
for Installation of Cellulosic and Mineral Fiber Loose-Fill Thermal
Insulation.
In wall applications standard practice is to compact loose-fill cellulose
to a density that will prevent settling. While this is a matter of some
controversy most authorities recommend a density of at least 3.0 pcf for
cellulose insulation in walls. Materials with high nominal settled
densities (2.0 pcf and higher) should be installed at 3.5 pcf. Research
has confirmed that settling is virtually nil with any cellulose
insulation at densities of 3.5 pcf, or higher. Compacting cellulose
insulation may produce a very slight reduction of R-value.
Specifiers do not need to compensate for settling in attics since
federal law (the CPSC standard and the FTC R-Value Rule) requires
R-value and coverage data to be stated at settled density. Open blow
cellulose installations do lose R-value as the material settles,
however such installations provide “bonus R-value” until they reach
settled density
Specifiers, installers, and buyers need to understand that the
"minimum thickness" column on cellulose coverage charts represents
settled thickness, if the chart has only one thickness column.
This is not done to confuse or mislead. It results from the fact that
there is no accepted procedure for determining blown thickness that
has been proven to correlate with the amount of material, by weight,
required to yield the desired R-value. ASTM is working on an appropriate
procedure. Some manufacturers provide initial installed thickness
recommendations, but this is only a guideline to aid installers.
The bag count and weight columns are the "official" coverage statements.
Installation of spray-applied cellulose is covered by CIMA Technical
Bulletin #3, "Standard Practice for the Installation of Sprayed Cellulosic
Wall Cavity Insulation."
This publication describes installation procedures that have been found to
be generally suitable for cellulose wall cavity spray installation, but
the instructions of the manufacturer should be followed.
All manufacturers and independent authorities agree that material with
low moisture permeability, such as a vapor retarder and foil or vinyl
wallcovering, should not be installed on both sides of the insulation
until the material has totally dried.
Drying time depends on several factors, primarily temperature and humidity.
Some electronic moisture meters can be used to determine when spray-applied
cellulose is dry. Not all meters will give accurate readings however,
because the fire retardants are electrolytes. Those using electronic
meters should be sure the device is suitable for cellulose insulation.
Many aspects of building design, including assemblies incorporating thermal
insulation, are still more “art” than “science.” After all code and
specification requirements are satisfied, the performance of an insulation
system is determined by the technical expertise of the insulation
manufacturer, the professional knowledge of the specifier, and the skill
and experience of the installer.
Bibliography
- American Society for Testing and Materials
- Annual Book of ASTM Standards Volume 4.06 Thermal Insulation; Environmental Acoustics, ASTM, Philadelphia.
- Cellulose Insulation Manufacturers Association, Technical Bulletin #2;
- "Standard Practice for Installing Cellulose Building Insulation."
- Cellulose Insulation Manufacturers Association, Technical Bulletin #3;
- "Standard Practice for the Installation of Sprayed Cellulosic Wall Cavity Insulation."
- Consumer Products Safety Commission
- Interim Safety Standard for Cellulose Insulation, 16 CFR Part 1209.
- Federal Trade Commission, Trade Regulation Rule;
- Labeling and Advertising of Home Insulation, 16 CFR Part 460.
- McElroy, D.L., and Kimpflen, J.F., editors
- Insulation Materials, Testing and Application, ASTM, Philadelphia 1990.
- Graves, Ronald S., and Wysocki, Donald C.;
- Insulation Materials: Testing and Applications, 2nd Volume, ASTM, Philadelphia 1991.
- Graves, Ronald S., and Zarr, Robert R..;
- Insulation Materials: Testing and Applications, 3rd Volume, ASTM, Philadelphia 1997.
- Lstiburek, Joseph, and Carmody, John;
- Moisture Control Handbook: New, Low-rise Residential Construction, Oak Ridge National Laboratory, Oak Ridge, TN, 1991.
- Nisson, J.D. Ned,
- Residential Building Design & Construction Workbook, Cutter Information Corp., Arlington, MA, 1988.
The performance story
The natural superiority of cellulose
Higher R-per-inch values than most comparable mineral fiber materials.
Tightens buildings against air infiltration much better than mineral
fiber materials. (Colorado University found cellulose at least 36 percent
better than fiber glass in tightening buildings.)
Not subject to convective heat loss, which has been shown to reduce
the actual R-value of comparable mineral fiber materials from 20 to
40 percent in cold weather. (Oak Ridge National Laboratory measured
actual values as low as R-12 at nine degrees F for an “R-19” fiber glass
installation. Oak Ridge found no R-value erosion with cellulose.)
"R" for "R" requires much less energy to produce than mineral fiber
materials, which are made in gas-fired furnaces. Productively recycles
the largest single component of the residential waste stream.
Rationalizes use of resources by putting trees cut to produce an
ephemeral product to long-term use as energy-conservation material. Overall,
insulates homes better. (Colorado University reported cellulose performs 26
percent better than fiber glass in temperate climates and as much as 38
percent better in cold climates.)
Cellulose....it's naturally better insulation
CIMA Technical Bulletins & Updates:
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to call us at: (330) 753-8394. We will be more than happy to assist you.
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