Technical data

16
Compressed Air Applications Manual | Selection of material and pipe system
Safety
The term “safety” covers a number of dif-
ferent aspects, such as:
• fracture behaviour
• resistance against UV radiation and
• compressor oils
• corrosion
• behaviour in fire
Since compressed air, contrary to water,
is compressible (“squeezed” into a small-
er space), mechanical damage to one of
the pipes may result in an explosion-like
expansion. It is therefore of vital impor-
tance that any mechanically damaged
pipes cannot become a danger to the
surroundings. For today’s compressed air
applications, one should only use plastic
pipes with ductile fracture behaviour,
even below freezing point.
Ductile fracture behaviour means that
splinter formation will not occur in the
event of forceful damage to the pipe cau-
sing an explosion-type expansion.
For polybutene (PB), the limit tem-
perature of the ductile behaviour is
≤ -5
0
C.
Any compressed air network will inevita-
bly contain traces of compressor oil and
condensate. In order to ensure a long
service life and maintain reliable opera-
tion of the compressed air system, the
pipe material must be highly resistant
against these substances.
Oil resistance of polybutene (PB)
Mineral oils, ester-containing oils and oils
with aromatic amines can have a nega-
tive impact on the service life of pipe
systems.
BEKOFLOW
®
is resistant against all
the usual compressor oils. We will be
happy to advise if you have any ques-
tions in this respect.
Corrosion behaviour
The material polybutene (PB) has the ad-
vantage that it is resistant against corro-
sion both from the inside and the outside.
In the case of steel piping, moist and
corrosive atmospheres always result in
corrosion from the outside, while residual
humidity in the compressed air produces
corrosion from the inside.
Plastic pipe systems made of PB are
non-corrodible; the quality of the com-
pressed air flowing through the pipes is
not affected.
Behaviour in fire
PB is a plastic material of fire class B2
conforming to DIN 41012 (normally flam-
mable).
In an open fire PB burns with a bright
flame. The fire gases smell of wax and
paraffin. Toxic or corrosive combustion
products – as occur with PVC or PVC-C
– are not possible with polyolefins like PB
because this material does not contain
halogens (chlorine).
Where fire protection measures are re-
quired for pipes passing through a wall
or ceiling, only use fireproofing arrange-
ments with corresponding approval.