HISTORY OF INSULATED PANELS & FIRE INSURANCE CONCERN
Insulated Panel History
Polystyrene (EPS) insulated panels became available in New Zealand and Australia over 35 years ago and were quickly recognized as a breakthrough in the construction of coolrooms, coldstores, chillers and freezers etc.
Compared with previous construction methods using masonry, cork & pitch, or timber framing with fibreglass batts, or multi-layered foil construction, EPS, panels were light-weight, strong, durable, modular and quick and easy to assemble on site. They provided a cleanable, moisture and vapour proof facing on both sides.
This also led to their acceptance in hygiene areas such as food processing plants.
With New Zealand’s extensive primary industries of meat, fish, horticulture & wine, EPS panels have been a major construction element.
Because of the nature of the products stored and processed in these buildings, fires have been relatively few, but when they have occurred, the damage has tended to be extensive. A recent example was the Takaka Dairy Factory fire. There have also been some very large fires in EPS panel buildings in Australia.
Fire History in UK
In the UK, and in Europe and USA, cool & cold stores were mainly constructed from polyurethane (PU) panels, which are less susceptible to fire, but EPS panels gained popularity in the UK for hygienic walls and ceilings within food processing buildings.
Some major fires within these food processing buildings in the UK resulted in a damning 1997 British Home Office report condemning EPS panels. As a result EPS panel construction in the UK was largely superseded by panels with mineral wool cores. While being non-combustible, mineral wool panels are also heavy, weak, and prone to moisture absorption. Also the fibres from exposed cores proved detrimental to food processing activities.
Mineral wool panels are, in addition, not suitable for temperatures below 5°C.
PU panels also became enmeshed with the EPS stigma and, in recent times, mineral wool and PU panel construction in the UK has largely been superseded by foamed polyisocyanurate (PIR) panels.
PIR panels have good fire resistance, very good thermal insulation values, but are relatively weak due to the poor mechanical strength of the foam and the thinner thicknesses used. Due to the more costly chemical composition and the sophisticated plant required to foam the panels in-line, PIR panels are also relatively expensive.
Insurance Concern in NZ
Since 9-11, the insurance industry has become more risk-averse world-wide. Following their adverse experience with EPS in the UK, overseas insurers and re-insurers started to focus on EPS panel buildings in New Zealand and Australia. This sentiment started to filter through to New Zealand brokers during 2003 resulting in increased premiums, the call for sprinklers in higher risk buildings and in some cases there was no insurance available.
The insurer’s main concern is that once ignited, EPS in panels tends to promote fire spread resulting in extensive fires and frequently total losses. Sprinklers are, of course, designed to stop a fire at source and minimise the extent of damage. However, water sprinklers in cold environments are neither simple nor desirable.
Now the revised Sprinkler Standard NZS 4541 has raised the barrier further with a more sophisticated level of sprinklers for cold environments. This standard contains levels of sprinkler protection required for buildings constructed with EPS panels – refer DZ4541 Section 213. This sprinkler protection is NOT required for buildings constructed with 'Approved Panels' that have passed FM Global testing or other approved testing regimes.
FM Global is an American based international insurance company that operates their own in-house test facility recognised world-wide. To achieve certification by FM Global, factory-manufactured insulated panels are assessed to FMRC 4880 (1994) – Approval requirements for Class 1 fire classification. Refer to the article Insulated Sandwich Panels and "FM Approved" by Andre J Mierzwa later in this section.
The FM Class 1 classification is a measure of the panel FIRE RESISTANCE –resistance to burning and resistance to spreading a fire throughout a building. This fire resistance is recognised in the NZ Sprinkler Standard which classifies FM rated panels as 'Approved Panels' which do not of themselves require sprinklers.
EPS panels on the other hand, when subjected to fire, melt, vaporise, catch fire and then promote the fire to the rest of the building. EPS panels are not 'Approved Panels' and do require sprinkler protection.
FIRE RATING normally refers to the ability of a building element such as a firewall to stop the spread of fire to a neighbouring property. A fire rating of say 30 minutes is a measure of the ability of a firewall to hold back a fire for 30 minutes.
With the almost exclusive use of EPS panel in New Zealand and the lack of a locally produced alternative, the choices for new construction has until now been stark -
EPS panel where acceptable to insurers, with significantly higher premiums
EPS panel with sprinkler protection, where acceptable to building users
Imported mineral wool panels in non-refrigerated areas
Imported PIR panels when sprinklers are not suitable, and EPS is not acceptable to insurers
PIR panel plants are being built in Australia but, with their high capital costs and requirement for continuous runs at constant thicknesses, there is unlikely ever to be a plant built in New Zealand.
But now there is an alternative:
PØLYPHEN® - a phenolic/polystyrene (PPS) composite foam developed in Melbourne, Australia over the last five years. Panel production commenced there in February 2005 and has been used in many projects including buildings for Arnotts, Woolworths, McDonalds and Boeing. PØLYPHEN® in curved sheet format is also being used to insulate large wine tanks.
PØLYPHEN® Panels have been made in New Zealand since early 2006 and have been used on many projects including buildings for Agrifeeds, Comvita, EastPack, Fonterra, Griffins, Goodman Fielder, Kaimai Cheese, La Bonne Cuisine and Tip Top.
PØLYPHEN® is a thermo-setting plastic that remains solid in a fire, charring like solid timber.
PØLYPHEN® does not promote fire and has been tested by FM Global and given a Class 1 Fire Rated classification (the highest classification) of fire resistance.
PØLYPHEN® Panels have also been tested for fire rating as firewalls and 100mm panels have a 45 minute fire rating.
PØLYPHEN® has a similar thermal insulation value to EPS and as it is manufactured at a higher density to S grade EPS, it is stronger in compression, bending and shear.
PØLYPHEN® is laminated into panel in the same manner and on the same production lines as EPS panel.
PØLYPHEN® is now being produced in Tauranga, New Zealand, and laminated into panel by leading panel manufacturers.
PØLYPHEN® Panels are assembled on site using the same construction details as EPS, the only discernible difference to the finished building being the presence of the prestigious FM Approval labels on each panel and a sign prominently displayed on the building to identify it to the Fire Service.
PØLYPHEN® Panel construction, of course, carries a cost premium over EPS panel, but is less expensive than using imported PIR panels, and is a preferred solution to installing sprinkler protection.