EPS Panels

[Bob Anderson IIA]

EPS panels became available in the 1980s and were quickly adopted in the construction of:
• cool rooms
• cold stores
• freezers.
There are a number of issues resulting from the use of EPS panels and the following two reports highlight the issues surrounding fire susceptibility.

Tip Top Bakery Fire

The following extract from a New South Wales (NSW) Fire Brigade report (2002) on the Tip Top Bakery Fire in Fairfield, NSW on June 2, 2002 acknowledges the fire susceptibility of EPS foam insulation panels:
Polystyrene foam is thermoplastic, that is, it softens when heated. Thermoplastic materials tend to melt and shrink away from heat long before ignition. This melting causes voids that reduce the structural strength of the panels. As the panels buckle, the joints tend to open introducing flame and air into the core.
This results in internal flame spread between the panels and throughout the structure and there is likely to be a rapid loss of structural strength and subsequent collapse of walls and ceilings.

Polyurethane (PUR) and polyisocyanurate (PIR) foams are thermosetting materials, which means that they do not melt, flow or drip when exposed to fire. Rather, they form a strong carbonaceous char that helps to protect the foam core and prevent flame spread within the panels themselves. It would appear that the sandwich panels utilised in the construction of the Tip Top factory were constructed with EPS insulation.
Construction using EPS sandwich panels presents several major difficulties for fire fighting:
• The loss of adequate structural integrity and subsequent likelihood of significant building collapse.
• The combustibility of the insulation material adds substantially to the fire load and results in the production of large amounts of heat, smoke and toxic products.
• Fire spread can be hidden within the panels, and this fire spread can be rapid, leading to conditions that favour flashover.


The following report from Zurich Australia (2011) outlines the lessons learned from a sandwich panel fire at a major food processing factory.
The fire started in a staging area for plastic packaging trays, and despite the area being attended and the presence of automatic smoke detection, the fire was able to quickly develop.
The fire was detected at an early stage by an operator who unsuccessfully discharged an extinguisher. Despite their best efforts, the fire quickly spread to the EPS (expanded polystyrene) sandwich panel ceiling.
Before the fire fighters could mount any first attack, the fire had spread the full length of the main production building, associated loading dock and cold store, overall a length of around 100 metres.
Over 100 fire fighters eventually attended and were able to contain the fire to the main building and protect the large ammonia receivers adjacent to the building.
The key lessons coming out of this fire was a reinforcement of previous experience:
• EPS panel ceilings are very susceptible to fires starting beneath them
• Fires starting under EPS panel ceilings spread very rapidly. The fire spreads across the ceiling as the panels progressively delaminate and the EPS melts and vapourises to fuel. Fires can also spread inside the wall and ceiling panels, before bursting out at the panel seams
• The fire load from EPS wall and ceiling panels is enough on its own to cause deformation and collapse of major steel roof beams
• Fire brigades are unlikely to contain a developed EPS panel fire and they will not enter the building due to the risk of collapse.

PIR sandwich panels
PIR sandwich panels are an alternative to EPS panels and some insurers classify this product as non-combustible.
The previous report from Zurich Australia (2011) concludes with an interesting footnote regarding the performance of approved PIR sandwich panels:
A new extension to the existing EPS cold store had been constructed from PIR. The fire burnt up to the PIR wall but did not penetrate (and) the PIR section was left largely intact. This tends to confirm our recommendation of approved alternative panels, be they PIR or Phenolic resin matrix.

[Bob Anderson IIA]

Best Practice- Cold Work Permits

Cold Work Permit Form
NB: No work is to be conducted on insulated metal panels with combustible cores without a permit.
Date Permit No.
Work to be Done




Location




Hot Work Yes / No
Is any hot work (cutting, welding, grinding) to be carried out?
Has a hot work permit been issued?
Penetrations
Does the work require penetration of the non-combustible outer layer of the panel?
If so what tools will be used to cut the panel?



Checks OK No N/A Action Required?
1. Production staff have been advised
2. No heat producing equipment to be used
3. Fire extinguisher and/or fire hose reel accessible
4. Sprinklers and other fire protection equipment is operational
5. Mechanical fastening of any fixtures
6. No electrical equipment or other potential ignition sources to be installed on or adjacent to panels
Authorisation (Responsible Officer)
This permit is valid from: ____ am/pm on ____/____/____ until: ____ am/pm on ____/____/____

Signed: Name: Title:


Operator (Person conducting work)
I understand that I am authorised to undertake only the work specified above on insulated metal panels with combustible cores.

Signed: Name: Title:
Final Check OK No N/A Action Required?
The authoriser is to re-inspect the work area at least 30 minutes after the completion of the works.
1. All joint strips that have been removed have been replaced
2. All exposed insulation and penetrations have been appropriately covered and sealed with metal plating
3. There is no evidence of fire, hot surfaces, or potential ignition sources
4. All waste materials have been removed

Signed: Name: Title:

[Bob Anderson IIA]

The following are our Best Practice Recommendations. The following controls are designed to avoid starting EPS fires. The objective is to keep ignition sources away from the combustible core of the panel.

Suggested Controls:

Always ensure that sparks or heat from cutting and welding is well separated from EPS panels.

• Never conduct cutting, welding, grinding or any other hot work directly on EPS panel.

• Do not mount electrical switches, panels, switchboards, or other electrical appliances directly onto EPS panels.

• Other ignition sources such as heaters, cookers, forklift rechargers and hazardous processes should not be located near EPS panels.

• Electrical panels and other equipment located in EPS areas should be maintained and tested on a regular schedule. Thermographic scanning should be undertaken on sub boards.

• Hot services such as exhaust ducts and heating lines which pass through EPS panels should have non combustible insulated sleeves fitted to prevent heat being transferred to the panel.

[Admin]

Zurich Article on working with EPS panels

Includes sample "Cold Work Permit"

[steve]

For the EPS building,Control the accidential ignition source seems not easy. such as accidental flying fire, wild fire, smoking and lighting fire and etc., So are there any loss control recommendations for them?

[Admin]

No I haven't seen any recommendations to cover those type of fires. Will see what I can find