SPRAYFOAM Professional - Spring 2014 - (Page 44)
A BA A
KEY CODE REQUIREMENTS FOR AIR BARRIERS -
HOW DOES SPF MEASURE UP?
BY LAVERNE DALGLEISH, EXECUTIVE DIRECTOR, AIR BARRIER ASSOCIATION OF AMERICA, INC.
ost building codes provide
requirements for air barrier systems that are additional to the basic
requirement that air leakage material
cannot be greater than 0.004 cfm/ft² at
a pressure difference of 1.57 psf (0.02 L/
(s·m²) at a pressure difference of 75 Pa).
The code typically starts with some general wording to provide the objective. An
example of this is the Commonwealth
of Massachusetts CRM 1304.3, which
"1304.3 Air Leakage
1304.3.1 Air Barriers: The building
envelope shall be designed and constructed with a continuous air barrier
to control air leakage into, or out of the
conditioned space. An air barrier shall
also be provided for interior partitions
between conditioned space and space
designed to maintain temperature or
humidity levels which differ from those
in the conditioned space by more than
50% of the difference between the
conditioned space and design ambient
conditions. The air barrier shall have
the following characteristics:"
The building code then goes on to
identify the key requirements for an air
"1. It must be continuous, with all
joints made air-tight."
This requirement is probably the
most critical detail for an air barrier
system. A lot of air barrier materials can
44 SPRAYFOAM PROFESSIONAL |
have extremely low air
leakage rates, but if they are
not continuous the joints can result
in air leakage. Spray polyurethane foam
(SPF) will not be continuous around all
six sides of a building, but can drastically improve most parts of the building.
As the material is installed onsite by
means of spraying, the SPF will provide a monolithic covering of the building assemblies. SPF by its nature, will
expand 30 times its original volume, it
seeps into cracks and holes, completely
filling them and making the installed
SPF seamless. Only when the material
is terminated and another air barrier
material is used on a building assembly do you need to ensure that there is
continuity. Because of its nature, SPF can
be installed over a very rough substrate
and although some of that roughness
will telegraph through the material, the
SPF will still provide a continuous plane
"2. It shall have an air permeability
not to exceed 0.004 cfm/ft2 under
a pressure differential of 0.3 in.
water. (1.57 psf.) (equal to 0.02L/s/m2
@ 75 Pa.)"
All medium density SPF will meet the
requirements for an air barrier material at the thinnest possible installation
thickness of ½ inch (13 mm). On the Air
Barrier Association of America (ABAA)
website, the materials listed range
from 0.000064 cfm/
ft² at a pressure difference of 1.57 psf (0.00032
L/(s·m²) at a pressure difference of 75 Pa) to as high as
0.0002 cfm/ft² at a pressure
difference of 1.57 psf (0.001 L/
(s·m²) at a pressure difference of
75 Pa). Light density open cell foam
can meet the maximum air leakage requirement but it is at a much
thicker material. The exact thickness
will depend on the manufacturer.
"3. It shall be capable of
withstanding positive and negative
combined design wind, fan and
stack pressures on the envelope
without damage or displacement,
and shall transfer the load to the
structure. It shall not displace
adjacent materials under full load."
SPF bonds to almost every substrate
unless the substrate is not clear or
Table of Contents for the Digital Edition of SPRAYFOAM Professional - Spring 2014
Executive Director’s Corner – by Kurt Riesenberg Our Place on the Timeline
President’s Post – by Bob Duke Foam in the Forefront
Foam Business News
Legislative Update – the Regulatory Avalanche
Are You Doing Something Stupid?
How Did I Make It Through Life Without This APP?
Respirators: Know Them. Use Them.
Operating Your Business Effectively: Legal Considerations and Managing Your Risk
Speaking Sensibly – by Mason Knowles Inspection of SPF Building Envelope Applications
Behind the Foam – the Insulation Man, Patrick Dundon
ABAA News – Key Code Requirements for Air Barriers
Calendar of Events
Ask the Expert
Index of Advertisers / Advertisers.com
SPRAYFOAM Professional - Spring 2014