After the new construction decisions in 2012, the lawful requirements for fire compartmentalisation have been changed.
A fire compartment is the maximal expansion area of fire within a building. Depending on the function of the building, there is a maximum size for fire compartments. For a use as lodge, this is 500 square meters, for offices, houses, sports and gathering usage, this is 1000 square meters and for industrial usage (both storage and workshop) 2500 square meters. For existing construction (renovation) there are alternate requirements (generally 2000 square meters for offices, etc. and 3000 square meters for industrial buildings).
If you want to realize a larger fire compartment, it is possible to request exemption of the compartment size based on equivalence. For instance, by installing sprinklers or heat/smoke exhausts or by storing a relatively small amount of flammable materials. The most used method to show equivalence is the Model Manageability of Fire (BVB).
Based on the present fire hazard (of the building and products inside) and safety level (sprinklers, heat/fire exhaust, fire proofing of walls) it is decided whether a proposed solution is equivalent. With this it is often possible to realize compartment sizes of 2500 up to 10,000 square meters.
However, sometimes it’s more cost efficient to compartmentalise, especially when partitions are already desired. Based on your specific situation we’d like to go through all available options.
Keep in mind that when your company building is built close to the plot border or another building, there will be requirements for the fire proofing of the outer wall. In many cases the used wall panels are sufficiently fire proof, but the main supporting structure which the wall is installed in must also be sufficiently fire proof. This can be achieved by (a) over dimensioning the entire construction, (b) fire proof covering, trapping and detaching by using tilting lugs at the concerning columns or (c) placing an extra fire proof column in between or in front of the existing construction. Here too, we would like to advise you on a project-to-project basis.
When designing a multitenant building, fire compartments can be chosen separately per unit, or as an overarching fire compartment. In this last case the underlying cadastral plot remains intact and ownership is decided per unit in an association of owners. When the plot is split cadastrally, every unit must receive their own fire compartments (60 minutes’ fire penetration). This can be achieved by separate constructions with a fire wall with fuse bolts on both sides in between or by placing a fire proof or over dimensioned column in the wall.
Often used terms:
• Fire penetration and fire spread
Fire penetration is the penetration of fire through a (inner) wall, fire spread is the spreading of fire through the outside air (for example across plot borders or roofs). When there’s a requirement of 60 minutes of resistance against fire penetration and fire spread (‘60 minuten WBDBO’, in Dutch) it means that it must take at least 60 minutes before a developed fire from one compartment can move into the next. To achieve this we must not only look at the applied roof or wall product, but also at the construction with which they’re connected.
Inner walls must satisfy an ‘EI’-requirement. This means that the applied product must not only be fire proof and remain structurally intact for the required amount of time, but there also cannot be any so-called ‘hotspots’ in the walls, which are more than 180 degrees warmer than originally. Because auto-ignition could occur in products in the protected compartment at those temperatures. Rock wool products or (aerated) concrete are suited for inner walls that satisfy the EI-requirement because of their high thermal capacity. PIR products are in limited amounts suited for inner walls (EI30).
Outer walls and roofs most satisfy the ‘EW’-requirements, the product must be fire proof and the radiation at a 1 meter distance must be less than 15 kW/m2, however, there can be hotspots on the walls. This is because it can’t lead to auto-ignition in a different fire compartment. In general, PIR products are suited for application in outer walls and roofs (EW).
• Permanent fire load
This is the total calorific value of all used construction materials summed up. This is decided by us. The sum total of the two fire loads (permanent + variable) decides, together with the presence or absence of sprinklers, the maximum compartment size.
• Variable fire load
This is the calorific value of all products stored, including packaging, vehicles, etc. This is usually decided by our client. The sum total of the two fire loads (permanent + variable) decides, together with the presence or absence or sprinklers, the maximum compartment size.
• The Building code
The Building code also sets requirements on the fire proofing on constructions, or the main supporting construction. These requirements depend on several factors like the height of the highest floor, the size of a compartment and the permanent fire load. In buildings where no compartments are ‘stacked’ (like in an apartment building) these requirements are lifted in most cases, when it’s not lifted it can be satisfied in several ways: Covering, spraying, filling with concrete or working into a wall.