Pipe wall thickness and insulation
Generally speaking, shorter compartment insulation is suitable for metal pipes with a smaller diameter, smaller wall thickness and lower thermal conductivity: with PROMASTOP®-CC soft penetrations of metal pipes with low thermal conductivity (λ ≤ 58 W/mK), pipe wall thickness 2,0 mm – 14,0 mm and pipe outer pipe diameter up to 42,0 mm require a non-combustible local insulation total centered penetration length of 500 mm; steel pipes with larger pipe wall thickness or outer pipe diameter need a minimum of 1000 mm long local insulation. According to the EN 13501-1 Standard, the reaction to fire classification of the local insulation in PROMASTOP®-CC soft penetration is a minimum of A2-s1, d0 or A2L-s1, d0; its melting-point is a minimum of 1000°C, bulk density is between 40 and 150 kg/m³, and thickness is between 30 and 100 mm. (Warning: this data is not the material characteristics of the mineral wool boards forming the soft penetration itself, as these are covered by a special provision; the thickness in the referred penetration is 1 x 50 mm, 1 x 80 mm or 2 x 50 mm, and the bulk density is minimum 140 kg/m³). The minimum required local insulation length for copper pipes with larger thermal conductivity (λ ≤ 380 W/mK), pipe wall thickness up to 14,2 mm and pipe outer diameter up to 42 mm, is 1000 mm; copper pipes with a larger outer pipe diameter (up to 88 mm) need a minimum of 2000 mm long local insulation.
Not only the Promat solutions require this complicated system, but all producers are expected to present the required insulation length in this way, according to the Test and Classification Standard.
Pipe end configuration
According to the EN 1366-3 Test Standard, four possibilities are determined based on the design of the metal or plastic pipe ends passing through the tested penetration, depending on whether the end of the tested pipe was closed inside and outside of the furnace (Capped, marked C) or was open (Uncapped, marked U).
Test condition |
Pipe end configuration |
Type of pipes |
|
Oriented inside (in furnace) |
Oriented outside (outside the furnace) |
|
U/U |
uncapped |
uncapped |
plastic: rainwater, ventilated sewage (drainage channel) |
U/C |
uncapped |
capped |
plastic: unventilated sewage; gas; drinking water, heating water (supply channel);
metal: non fire-resistant suspension/coupling systems, waste disposal shafts made from pipes
|
C/U |
capped |
uncapped |
metal: fire-resistant suspension/coupling systems |
C/C |
capped |
capped |
/ |
The behavior of the specimen during the test is fundamentally determined by the design of the pipe end: the pressure and flow of hot gases are different in (an open) pipe that is in contact with the atmosphere than in a capped pipe, so when choosing the suitable fire protection solution the proper pipe end configuration must be taken into account as well, and not just the usual EI XX fire classification. Certainly all readers have already seen the U/U or U/C mark in the fire classification of a modern fire collar, which was explained above (i.e. a pipe open on both ends has a U/U configuration, which is the worst-case scenario from a fire protection point of view, so all solutions with this classification are suitable for any pipe ends).
Let’s take a look at these marks referring to the given installation positions and structural establishments in the classification of fire-stopping collars PROMASTOP®-FC (powder-coated stainless-steel body with intumescent inlay) and PROMASTOP®-FC MD (cut-to-length collar) and PROMASTOP®-W fire-stopping wrap. The pipe end classification may differ in light or solid wall, in a soft penetration or core drilled hole, in wall or floor penetration.