MIS.002.001.0200
EECA position on reflective
pliable membranes
By Gleb Speranski,
Team Manager Technical
MIS.002.001.0201
Decision to stop using foil
Quality of foil installations under EWHG was generally
poor and EECA struggled to improve quality.
Since 1 July 2008 EECA stopped funding foil under
EnergyWise home grants (EWHG) programmepredecessor of WUNZ:HS.
MIS.002.001.0202
Three main issues with pliable
reflective membranes {foil):
• Durability
• Performance
• Safety
MIS.002.001.0203
Durability
Factors impacting on durability: of foil installation:
•
•
•
difficulties to install foil well. It is easier said than done.
High rate of failures with foil installations. If foil installation
has failed it is practically impossible to fix.
If foil is not installed well, it is more likely to fail sooner due
to impact from animals, weather, trades people, etc.
Even if foil was installed well its durability is still limited due
to above factors. BRANZ report identified cats and
plumbers as two most serious enemies of foil installations..
MIS.002.001.0204
Difficulties installing foil
MIS.002.001.0205
Performance
•
•
•
Performance and durability are directly linked to each
other: no durability- no performance.
Even in ideal installation actual in situ performance of
foil will vary depending on ambient temperature and
heating regime in the house. BRANZ testing shows
negligible R-values in some cases. It is hard to project
energy savings with such a variability in performance.
Poor installation practices impact greatly on
performance of foil. If air cavity between the floor and
foil is not sealed the air will still move resulting in poor
R-value.
MIS.002.001.0206
Other factors impacting on durability
and performance of foil (under floor)
The latest from BRANZ on foil is issues with moisture.
BRANZ found that attempts to further seal the cavity
between foil and the floor may cause condensation on
top of foil. This condensation will cause the following
.
1ssues:
• Loss of reflectivity (and therefore performance)
•
•
Deterioration of foil
Moisture absorption by adjacent building elements
(such as floor joists and boards).
MIS.002.001.0207
Foil creating a vapour barrier
MIS.002.001.0208
Safety
•
EECA is aware of three fatalities on foil
installations in New Zealand
• Anecdotally every installer had an electric shock
at least ones (when interviewed informally many
admitted several shocks).
• Safety precautions outlined in NZS 4246 cannot
guarantee safety of installers.
•
In a number of cases electrically neutral foil
installation became live after foil was installed.
This creates significant risk for house occupants
and service men.
MIS.002.001.0209
Safety challenges with foil
MIS.002.001.0210
EECA prod uct policy
New EECA product policy sets rigorous requirements for
insulation products.
Other than compliance with AS/NZS 4859.1 for product
quality insulation products are expected to:
- Meet requirements of New Zealand Building Code/Act.
- Must be able to install correctly.
- Must perform over their stated life time.
-
As installed, must be amenable to independent check
testing.
Must not endanger health and safety of installers and
occupants.
Should not cause deterioration or damage to any part
of the house.
MIS.002.001.0211
Alternative solutions
Bulk insulation proved to be a good
alternative solution with semirigid products being leaders.
Benefits of using bulk insulation
include:
- Easier installation
- Better thermal performance
- Improved durability (up to 50
years with some products).
- Fit for purpose
- Safer installation
MIS.002.001.0212
MIS.002.001.0213