Frøslev fire retardant treated wood

FRØSLEV FIREPROOFING OF PROFILES FOR INDOOR AND OUTDOOR CONSTRUCTION

The ingredients of the fire retardant proofing process make sure that the flame spread of the wooden surface as well as heat and smoke generation are drastically reduced, giving people in and around buildings the time necessary to reach safety.

Frøslev fire retardant is fire-proofed with Dricon.

Frøslev fire retardant

Frøslev fire retardant wood for exterior and interior cladding. The fire proofing is done on tongue and groove profiles and strip panelling, board roofs and bond timer, timber and boarding. The fire proofing is with non-toxic, non-hygroscopic fire retardant and is in the EU fire classes B-s1,d0 and B-s2,d0.

Wood species

We fire-proof the following wood species with dressed and paintcut surfaces, respectively (not rough surfaces):

  • Spruce
  • Pine
  • Frøslev Heatwood
  • Western red cedar
  • Oak
  • Douglas
  • Ash
  • Larch

Finishing treatment and maintenance

Inside, the cladding can be left untreated - outside, Frøslev fire retardant must be painted with an approved Drywood Firestain paint. Frøslev can provide the overall solution for exterior use with both Dricon fire proofing and Drywood Firestain painted with 1 x primer and 1 x intermediate layer. We can deliver painted surfaces in all RAL colours. It is also possible to choose your own and apply the surface treatment at your own risk. In that case, the Drywood Firestain instructions must be followed.

Ratings

Frøslev fire retardant is approved according to fire category Euroclass B-s1,d0 or B-s2,d0 and boarding class K1 10. The wood is FSC- or PEFC-labelled as well as CE-marked. The façade cladding, roofing boards and panelling are also TGA-approved.

Frøslev fire retardant is ageing tested according to EN 16755, see the product TGA.

 

Benefits of Frøslev fire retardant

Frøslev does the fireproofing at our own plant with third party control. The way from order to production is short, so we do quick delivery. The products can be loaded with other goods and delivered directly to the construction site on request. We have a large profile programme of which a large part of the products are stocked and can be fire-proofed.

We provide professional guidance. Contact our knowledge partners within the field of fire and receive quick and accurate offers with relevant approvals. 

 

Get the complete solution with products painted according to an approved paint system, and you will not have to do the first treatment on the construction site.

Understand the fire classes better

Material:

  • A = Incombustible
  • B = Fire-retarded
  • D = Not fire-retarded, untreated

Smoke: 

  • s1 = Very limited smoke generation
  • s2 = Limited smoke generation
  • s3 = No demands on smoke development

Burning droplets:

  • d0 = No burning droplets
  • d1 = Limited droplets
  • d2 = No demand

Construction:

  • Covering: E.g. concrete / wind barrier K1 10, B-s1, d0
  • Rain shield: Fireshield class B-s1, d0

Frøslev products:

  • Fireshield spruce: K1 10, B-s1, d0
  • Fireshield profiles: K1 10, B-s1, d0
  • Fireshield pine: K1 10, B-s2, d0
  • Fireshield larch: K1 10, B-s2, d0
  • Fireshield panelling: K1 10, Bs2, d0

Production with Dricon

Dricon

Dricon is a water-based and moisture-resistant, non-hygroscopic proofing designed to last the entire life of the building. The benefits of using Dricon rather than salt-based formulations include i.a. the following:

  • Does not react with metal parts
  • Can tolerate humid environments and changing temperatures
  • Accepts approved surface paints without leaching
  • Has very low smoke properties in case of fire

The carefully controlled treatment proofs and penetrates all sides of the wood boarding, thus creating permanent, long-term protection requiring minimal maintenance - a major benefit compared to short-lived or fire-like proofing products applied at the construction site without checking the layer thickness and penetration.

Depending on the type of wood and profile, the product can be

  • CE-marked according to EN 14915
  • classified as class B-s1,d0, see DS/EN 13501-1

The Dricon process

The Dricon fluid is pressed into the wood in a carefully controlled process with vacuum and pressure at our own impregnation plant in Frøslev. The wood is then kiln-dried to achieve a shipping-dry moisture content of 15-19% - or alternatively a moisture content requested by the customer.

The procedure is as follows:

  1. Wood for cladding is placed in an autoclave, and the initial vacuum is made. The cells of the wood are thus emptied of air, and the vacuum is maintained. 
  2. The tank is filled with Dricon fire-proofing solution under vacuum.
  3. The autoclave is put under hydraulic pressure, driving the Dricon fire-proofing solution into the cells of the wood.
  4. The final vacuum drains out the excess solution and then pumps it back to the storage tank.
  5. The underpressure in the wood draws in the surface treatment as the pressure returns to normal. Treated boards are then kiln-dried to a specified moisture content.

Fire requirements

Fire requirements to note during construction

Many people mistakenly believe that it is difficult to build with wood when conversation turns to fire. However, contrary to what many people believe, wood is in fact very fire-resistant and often acts better in a fire than for example steel. With the proper dimensions, a wooden structure such as a sports centre will last longer than one made of steel.

This is because steel heats up relatively quickly and starts to bend. However, a wooden structure retains its strength much longer and does not collapse until hardly any wood is left - the wood will burn, but quite slowly, only between 0.6 and 0.8 mm/minute.

Before getting started

Consider:

  • Is it 'inside cladding', 'outside cladding' or an 'outside rain shield'?
  • Are you within the 20 % rule?
  • Is the fire requirement: D-s2, d2 / [K1 10] D-s2,d2 or B-s1, d0 / [K1 10] B-s1,d0 - or a fire separating requirement, e.g. class:
    - R 30 - load-bearing, but not separating element
    - EI 30 - not lead-bearing, but separating element
    - REI 30 - load-bearing and separating element

Once those 3 points have been checked, you are ready to describe what materials should or can be used.

 

The rules in brief

According to current rules, large building in use classes 1-6 can be built and clad with wood for up to 20% of the façade area - known as the 20% rule. There are no other requirements for the wooden part other than the part having to comply with covering class [K1 10] D-s2, d2. For properly profiled wood, this is not a problem, and the wood will comply with class [K1 10] D-s2, d0 without additional treatment. (d0 is better than d2).

The 20% rule does not apply to one-storey buildings. In that case, the entire façade may be made to comply with class [K1 10] D-s2, d2, i.e. properly profiled wood with a ventilated cavity behind.

HOWEVER, for buildings in use classes 1-6 with a floor height up to and above 22, the entire façade may also be clad with wood - as long as the covering class requirement [K1 10] B-s1, d0 has been met. This can be done when the cladding has been tested to meet the [K1 10] B-s1, d0 requirement. However, this is usually not a practical option as cladding typically must be made with a ventilated cavity behind in order to dry and as it is a requirement that the internal fire separation wall is fully extended to the external cladding. In this case, that is not a practical option.

Therefore, the wind barrier must be seen as the external cladding of the façade, and that is the one that must meet the requirements for covering class [K1 10] B-s1, d0. The wooden part of the façade is thus made into the rain shield of the façade, and the requirement for the material is "only" class B-s1, d0 - wood in itself cannot achieve that, but it can once it has been e.g. fire-proofed.

There are also various ways to compensate for, i.a. by using automatic sprinkler systems and façade sprinkling.

Interior woo lining

However, if you want an interior* wall with wood lining, you should look at the wood as part of the unity of the wall and know which requirements apply to fire separation etc. In that case, the wood is part of the overall construction and must have been tested for/must meet the requirements for covering class [K1 10] B-s1, d0 (when required). This is often achieved by combining fire-proofed wood with a base of a different, protective material.

The Construction Products Regulation (CPR) also requires that wood for interior lining and exterior cladding is supplied with the CE marking, see EN-14915.

 

*Special and more lenient rules apply to wood for interior use in e.g. single-family houses.