Durability - a vital part of satisfactory fire protection

Durability - a vital part of satisfactory fire protection

Durability - a vital part of satisfactory fire protection

The durability of the fire protection can be literally vital. If there is a shortage in durability, people live in false security. This can cause large extra costs for builders and property owners.

The durability of fire protection is all too often overlooked.
Unfortunately, fire protection treatments do not always have the durability promised.
It is vital that timber products are properly treated with fire protection and thus provide permanent protection.
It is therefore also important that the fire protection treatment has been properly tested.
Deficiencies in handling can quickly have dull consequences when a facade is exposed to weather, moisture and wind

Must check the resistance
Many people think that they are building completely fireproof, but it is not always obvious.
Too many builders and contractors feel safe because they bought a wood product that has B-s1, d0 or SP-Fire 105.
Unfortunately, this is not always the case.
They may not have checked the long-term resistant properties of the fire protection agent.
A product may be certified or classified for the current fire class - but it does not help if the impregnated wood panel or fire protection paint cannot be proven to have approval for long-term durable properties according to EN16755 or CEN / TS 15912 DRF, -INT 1, -INT 2 and EXT.

The builder is responsible
The latter is a shall-requirement. It determines whether the product is approved for use in an exterior environment, for example as a facade cladding for multi-storey buildings.
An approval according to EN16755, CEN / TS 15912 DRF EXT shall be stated in the type-approval certificate.
It is the only way to confirm whether the product is approved or not.
It is the builder and / or the developer who is responsible for controlling the durability via documents - an important feature that is rarely written into the prescriptive text, but which is directly crucial for the long-term function.

Long-term security
A durable fire protection should provide long-term protection against fire - for individuals, economic values ​​and society at large.
A fire protection impregnated wood panel must therefore be treated so that it protects for many years, not just the first time.
A wood panel impregnated with fire protection products that are not certified according to EN 16755, CEN / TS 15912 DRF EXT is not a suitable product to use.
It is not a fireproof investment when an inadequate protection deteriorates and leaches over time.

Expensive renovations
Lack of durability in the fire protection agent is a growing and insidious problem.
It is not good enough with baseless statements, praises and promises.
Choosing fire protection should never just be a matter of fast deliveries or low prices.
Tenants are then tricked into a false security and property owners can be forced to expensive renovations.
Such things become inevitable as the fire protection disappears and in the worst case no longer meets the fire requirements that apply according to the Swedish National Board of Housing, Building and Planning's BBR.

Require type approval certificate
An important and well-rounded advice to builders and builders reads:
Never use wood panels that have been fire-treated without the type-approval certificate for long-term durable properties. This applies to both impregnation and protective painting.
Deciding whether to use a product or perform fire painting that does not have proven durable properties - is to disregard one's responsibility.
It means a lottery with the security and can cost lives.
It is also a safe way to get large future maintenance costs, as products that do not have permanent properties must be renewed and maintained at short intervals.

It is visible when fire protection has leached
There are many examples of how fire protection has been used with a lack of durability.
It is visible to the naked eye when the fire protection of wooden buildings' facades is out of order.
When a non-persistent fire protection agent is leached out, the surface of the wood panel is covered with a white powder-like substance. This means that the panel has lost the ability to withstand fire and destruction. It must then be replaced.
This means that large sums are also leached out of the responsible builder's cash, to replace a panel is an expensive process.
It can only be avoided by doing it correct from the start.

Risk of financial setback
It is the builder who bears the responsibility for the fire safety of buildings.
Not choosing a prescribed product but "an equivalent product", without documented and lasting properties - means risking both an economic setback and damage claims.
The responsibility does not lie with the supplier of the defective and non-permanent fire protection material.
It is the downstream user's responsibility to ensure that the product used in place of the prescribed has the required properties.
Therefore, it becomes cheaper to procure a prescribed product with properties approved by the expert, compared to taking a cheaper product from a supplier who is unable to prove a certified documentation from an independent third party, a product that does not have to be replaced after a short period of time.

It's about choosing the right product
The difference in the durability of fire-resistant products can be compared to that of clothing.
A dark sweater that is poorly dyed and has defective fibers can do well indoors, but after a day in the sun, or after the first wash, you notice marked deterioration.
Similarly, it is with wood products with a fire protection with a lack of durability.
Therefore, it is important to choose the right among the products which according to EN 16755 are divided into three different DRF classes (Durability of Reaction to Fire) - the European standard for fire-protected wood products' use classes. 

Mold and health problems
INT-1 – the least demanding of the DRF classes, refers to permanent use indoors. Common deficiencies are that the wood panel is treated with fire protection paint and impregnation with negative hygroscopic properties that can, among other things, contribute to mold growth.
INT-2 – a tougher class, for permanent use indoors, in weather-protected environments, and in environments with higher and varying ambient humidity ratios than normal indoor climates, e.g. attic spaces, cold storage, etc. A common problem is that the product does not withstand changing climates. Moisture infestation can then cause molding, release of paint and leaching. It can cause health problems if mold spores are spread in the property, as well as entail large remediation costs.

The weather affects
EXT – the toughest class, for permanent use in exterior environments like wooden facades with verified durable fire-technical properties. Those products are also subjected to fire tests. But a common mistake is that you just look at the fire-technical properties in new condition and forget what happens in a harsh climate with rain, UV radiation, temperature differences and wind.
In the worst case, the result can be devastating. Partly because the fire protection resistance deteriorates at a rapid and unauthorized rate, and partly that beautiful wooden facades become crowded and destroyed. This can result in huge costs for everyone involved.
Worth noting is that the requirements for durability are based on the deterioration of input data in relation to output data, not against specific fire class.

Different test methods
There are various test methods to test the durability of fire-treated wood products.
The tests concern the hygroscopic properties of the fire protection agent and long-term fire technical properties after weather exposure - not the type of wood as such.
The most common method is accelerated aging, as natural aging is a test that takes a long time. The basic principle of the accelerated aging test method is that the material in the climate chamber is exposed to recurrent cycles that simulate the exposure of rainfall, heat, drying and UV radiation.
All to ensure that the fire protection treatment has permanent properties.


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Knowledge area Sustainability
Area of Method Fire impregnation
Author Hans Olov Ohlson
Location Sverige