OVERVIEW
What is Fiber Glass Metal Building Insulation?
Fiber glass insulation for metal buildings is called NAIMA 202-96®(Rev.2000)
insulation. The standard designation means the insulation meets the
requirements of the NAIMA 202-96 (Rev.2000) Standard and is certified
for thermal performance by the National Association of Home Builders (NAHB)
Research Center for use in metal buildings. Once the unfaced
insulation is produced, a vapor retarder is applied to the fiber glass
blanket by a laminator, and the insulation is re-rolled and compressed
for shipment to the job site in custom lengths and widths to fit the
building.
What Does Metal Building Insulation Do?
Controls Heat Flow
Metal building insulation acts as a barrier to slow down the
movement of heat, keeping it inside the building in winter and
outside the building in summer. By controlling the rate of heat
transfer through the building, insulation reduces energy
consumption, resulting in lower fuel bills and a cleaner
environment. |
Prevents Condensation
Metal building insulation with a vapor retarder facing limits
the passage of water vapor and prevents it from condensing within
the insulation or on the interior surfaces of the building. |
Controls Noise
Metal building insulation greatly reduces the level of both
exterior and interior noise by reducing transmission of exterior
sounds to the interior of the building and absorbing reverberating
sounds within the building. |
Increases Lighting Efficiency
The laminated facings on the insulation provide a bright,
attractive wall and ceiling treatment that acts as a reflector to
increase lighting efficiency. |
Job Site
Storage Recommendations
The insulation should be inspected upon arrival at the job site to
ensure that it is exactly as ordered. If there is anything wrong with
the insulation, it should not be installed. Contact the supplier
immediately.
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Insulation should be stored in a dry, protected area. (See photo
A)
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All packages should be elevated above the ground or slab,
preferably on a flat surface, to prevent contact with surface
water accumulation. The facing should be protected from tears and
punctures to maintain continuity of the vapor retarder. (See photo
B)
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Poly-bags should have holes in each end to aerate the insulation.
It is also suggested that the contractor open the ends of the bags
to allow better air circulation around the insulation. (See photo
C)
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Packages can be left uncovered during the day, weather permitting,
but should be protected at night with polyethylene film, canvas or
other covering.
NOTE: Whenever possible, the insulation
should be used as soon as possible after it arrives at the job
site. The sooner the insulation is installed, the less likely it
is to get damaged in storage |
U-Values
The U-value (overall heat transfer coefficient) is a term used to
describe and specify the thermal performance of a building envelope
assembly such as a roof or sidewall system in a metal building.
U-value applies to a complete assembly that has a number of heat flow
paths. Each path contains materials in series heat flow.
(U-values required for cities and states across the U.S. are
contained in NAIMA publication "ASHRAE 90.1 Compliance for Metal
Buildings.")
Vapor Retarders
The vapor retarder used on metal building insulation should be
strong enough to withstand handling during installation as well as
to function as an aesthetically pleasing interior building finish.
Therefore, the facing must have good tensile strength, good
rip-stop characteristics and puncture resistance. In addition, it
must be fire retardant, provide good light reflectivity, provide a
durable, yet aesthetic, appearance and have a low water vapor
permeance. (Permeance is a measure of the flow of water vapor
through a material). The lower the permeance the better the vapor
retarder. Table 1 is a list of typical vapor retarders. |
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Vapor retarders function as an aesthetically
pleasing interior building finish and should be specified to last
the life of the structure. |
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Table 1: |
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Vapor Retarder Type |
Typical Perm Rating |
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Vinyl |
1.0 |
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Polypropylene/Scrim/Kraft (PSK) |
.02 - .09 |
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Foil/Scrim/Kraft (FSK) |
.02 |
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Polypropylene/Scrim/Foil (PSF) |
.02 |
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Vinyl/Scrim/Metallized Polyester (VRP) |
.02 |
Installation Methods
There are a variety of methods for installing metal building
insulation. Some are applicable for both new and retrofit
construction, while others are suitable for new construction only.
These installation methods are not meant to be an endorsement but,
rather, to acquaint the reader with a number of insulation application
methods. Some metal building manufacturers may have very specific
installation procedures which must be followed to comply with
warranties. Some of these are patented systems and their use may be
restricted. We suggest consulting with the building manufacturer
before specifying installation procedures.
Workability Temperatures
It is important to remember that installing faced insulation is not
recommended when the temperature falls below the minimum workability
temperatures shown in Table 2.
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Table 2: |
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Minimum Workability Temperatures |
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Vinyl |
40°F |
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Polypropylene/Scrim/Kraft (PSK) |
20°F |
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Foil/Scrim/Kraft (FSK) |
10°F |
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Polypropylene/Scrim/Foil (PSF) |
20°F |
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Vinyl/Scrim/Metallized Polyester (VRP) |
20°F |
ROOFS
Installation Over Purlins
| Insulation should be in
lengths that will cover the distance from eave to eave plus an
extra 12" on each end to overhang each side of the building. In
situations where more than one roll is necessary to span the roof,
a ridge pan should be used (see illustration to the right). The
width of the first run of insulation should be one foot wider than
the width of the roofing panel. Succeeding runs should be either
the same width or twice the width of roof panels. This is done for
ease of seaming. |
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Installation Method
Starting at an end wall of the building, temporarily secure one end
of the insulation to the eave strut by using either a spray adhesive,
double-faced tape, or mechanical fastener (screws, washers, metal
banding or strips). Unroll the insulation across the purlins with the
vapor retarder towards the interior. Keep tension on the insulation
while the metal panels are being attached over the insulation. This
prevents excessive drape which can result in large voids above the
insulation and assures the attainment of U–value requirements. Do not
overstretch the insulation. This can result in over-compression and
reduced R–value. Fasten the insulation at the other eave in the same
manner as the first eave. Install the next roll of insulation in the
same manner, making sure the rolls are stretched tight (but also allow
for full recovery of the insulation blanket), aligned properly and
closely butted, and seal the insulation tabs by one of the methods
described in the Tab Fastening section.
Installation in Standing Seam Roofs
This installation method is used to install metal building
insulation in standing seam roof systems. The use of thermal
blocks may be optional since the standing seam roof sheets hold
the roof above the purlins, thus reducing the compression of the
insulation. A second layer may also be added (see below) if
desired. |
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Thermal Spacer Blocks
To reduce thermal efficiency loss where the insulation is
compressed between the purlins and the roof sheet, thermal blocks
of rigid polystyrene foam should be installed. These blocks are
placed on top of the insulation at the structural members and may
be temporarily held in place with double-faced tape or spray
adhesive until the roofing panels are put on. |
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Two-Layer Installation Systems
There are two types of two-layer installation systems, each
providing a significant increase in thermal resistance over a
single layer system. |
First Method
The first method for installing metal building insulation uses
the exact same method as that used to install insulation over
purlins. The one difference is that the insulation is allowed to
drape slightly between each purlin so that a second layer of
unfaced insulation can be installed parallel to, or between each
purlin. |
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Second Method
The second method of two-layer installation is to install rigid
fiber glass insulation board (48" x 120") with vapor retarder on
the underside of the purlins, held in place by mechanical
fasteners. Unfaced metal building insulation is then installed
between the purlins and on top of the rigid board. For maximum
efficiency, in standing seam roofs, thermal blocks of polystyrene
rigid foam may be installed on top of the purlins with
double-faced tape or spray adhesive. Roof panels are mechanically
fastened to the top of the purlins through the thermal blocks.
When installing insulation between the purlins, a support
system can be used in place of the rigid board. Several options
are available. One is to make a lattice type support using cross
banding that is attached to the bottom or placed through the
purlins and anchored to the eave strut with support bands. Next,
support bands are placed on top of and perpendicular to the cross
bands, forming the lattice system. There are a number of patented
insulation installation and support systems available, which will
provide a suitable support system. |
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SIDE AND END WALLS
| The most common method of
insulating side and end walls of metal buildings is the standard
method of rolling insulation down the walls. Faced metal building
insulation should be cut to length plus an additional 12&Mac178;
(minimum) per sheet for overhang.
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Unroll the insulation and cut the dimension from base angle to
eave strut or rake plus 12" extra.
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Install the facing toward the building interior. The width of the
first run of insulation should be 12" wider than the width of the
wall panel. Succeeding runs should be either the same width or
twice the width of wall panels. (See Photo D)
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Attach the insulation to the eave strut of rake angle with clamps
or double faced tape. (See Photo E)
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Pull from the bottom end to stretch the insulation tightly outside
the girts from the eave or rake to the base angle.
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Before insulation is attached to the base angle, the extra fiber
glass should be carefully cut off (approximately 6") and then
removed from the facing. Be careful not to cut the facing. After
removal of the extra of insulation, fold the extra facing up over
the insulation at the bottom and staple to the side tabs to hold
in place. Attach to base angle with double faced tape. Maintain
the bottom of the insulation 1/2" above the base flashing. (See
Photo F)
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Attach the metal wall panel to the structure according to the
manufacturer’s instructions.
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Place the next roll of insulation in the same manner with edge
butted snugly, and fasten tabs using one of the methods described
in the Tab Fastening Instructions section.
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If there is no base trim, use a foam or rubber closure. If rodent
protection is needed, a foam or rubber closure is recommended.
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Tab Fastening Instructions
There are a number of different methods for fastening metal
building insulation facing tabs. Most facings are 6" wider than the
laminated insulation. The extra facing may be supplied as two 3" tabs,
or one 6" tab for all other products. It is recommended that the first
roll of insulation (starter roll) be at least 12" wider than the width
of the metal roof or wall panel being installed. This ensures the
insulation joints are not lined up with the metal panel joints and
prevents working directly at the edge of a panel when folding and
stapling the tabs.
Two 3" Tabs
If two 3" tabs are supplied, use a plier stapler to fasten the
facing tabs together where two adjoining pieces of insulation butt
together. First, pull the facing tabs in between the blankets,
away from the inside of the building. Then staple approximately
every 4" at approximately 1/4 to 1/2" from the edge of the tabs.
(See Figure 1a.) After stapling the tabs, fold them over to tuck
them between the insulation blankets and staple again. (See Figure
1b.) |
One 6" Tab
When working with a 6" tab, spray or brush a good quality
moisture-proof adhesive on the back. (See Figure 2.) Extend the
tab over the facing of the adjacent roll of insulation and press
firmly with a damp cloth along the seam to smooth it and remove
excess adhesive.When working with a 6" tab, spray or brush a good
quality moisture-proof adhesive on the back. (See Figure 2.)
Extend the tab over the facing of the adjacent roll of insulation
and press firmly with a damp cloth along the seam to smooth it and
remove excess adhesive. In cases where continuity of the vapor
retarder properties of the facing is not critical, it is common
practice to install as described, but without the use of adhesive. |
Miscellaneous
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Cover any rips or tears with matching facing tape to ensure a tight
seal. Do not use patching tape to seal tabs.
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Trim excessive insulation flush at eaves and rakes to prevent it from
acting as a wick to draw water into the building.
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Since building and insulation systems differ, it is important that the
contractor adhere to the particular erection instructions furnished by
the metal building manufacturer and the laminator supplying the
insulation.
Clothing and Equipment
Clothing
When installing fiber glass insulation:
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Loose fitting, long-sleeved and long-legged clothing is recommended to
prevent irritation. A head cover is also recommended, especially when
working with material overhead. Gloves are also recommended. Skin
irritation cannot occur if there is no contact with the skin. Do not
tape sleeves or pants at wrists or ankles.
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To minimize upper respiratory tract irritation, measures should be
taken to control the exposure. Such measures will be dictated by the
work environment and many include appropriate respiratory protective
equipment. See OSHA's Respiratory Protection Standard.
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When appropriate, eye protection should be worn whenever SVF Products
are being handled.
For more complete information, please refer to NAIMA publication
Working Smart with Fiber Glass, Rock Wool and Slag Wool Products -
Recommended Work Practices for the Installation of Synthetic Vitreous
Fibers (SVF) (N027).
Equipment
For cutting insulation, the best knife has been found to be one
with a serrated blade. Blades should be replaced periodically as they
tend to dull during use. Other equipment may be preferred by the
installer. Tools that generate the least amount of dust should be
used. If power tools are to be used, they should be equipped with
appropriate dust collection systems as necessary.
Fall Protection
Installing Insulation on Metal Building Roofs
Installers engaged in insulating low slope roofs with unprotected
sides and edges 15 feet or higher* or more should be protected from
falling by: guardrail systems, safety net systems, personal fall
arrest systems, or a combination of a warning line system and
guardrail system, warning line system and safety net system, warning
line system and personal fall arrest system, or warning line system
and safety monitoring system.
Installing Insulation in Metal Building Sidewalls
Insulation installers working on, at, above, or near wall openings
where the outside bottom edge of the wall opening is six feet or more
above lower levels, and the inside bottom edge of the wall opening is
less than 39 inches above the walking/working surface, must be
protected from falling by the use of either a guardrail system, a
safety net system, or a personal fall arrest system.
* OSHA 29 CFR 1926 subpart
R.
About NAIMA
NAIMA is the association for North American
manufacturers of fiber glass, rock wool, and slag wool insulation
products. Its role is to promote energy efficiency and environmental
preservation through the use of fiber glass, rock wool, and slag wool
insulation, and to encourage the safe production and use of these
materials.
In May 1999, NAIMA began implementing a comprehensive voluntary work
practice partnership with the U.S. Occupational Safety and Health
Administration (OSHA). The program, known as the Health and Safety
Partnership Program, or HSPP, promotes the safe handling and use of
insulation materials and incorporates education and training for the
manufacture, fabrication, installation and removal of fiber glass,
rock wool and slag wool insulation products.
For more information, contact:
NAIMA
44 Canal Center Plaza, Suite 310
Alexandria, VA 22314
Phone: (703) 684-0084
Fax: (703) 684-0427
E-mail:
click here for online contact form
web site:
http://www.naima.org
NAIMA Metal Building Committee Members
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