Appearance (water
pipes)
Black Pale grey-beige Blue Grey-beige Black
Sound produced
when dropped
Medium clatter High clatter High clatter High clatter Dull thud
Combustibility
and appearance of
flame
Bright flame:
Drops continue to
burn after falling
Bright flame:
Drops continue to
burn after falling
Carbonises
in flame:
Extinguishes away
from flame
Carbonises
in flame:
Extinguishes away
from flame
Bright flame;
Drops continue to
burn after falling
Odour of smoke
after flame is
extinguished
Like candles Like resin Pungent like
hydrochloric acid
Pungent like
hydrochloric acid
Like candles but
more acrid than
HDPE
Nail test
(impression made
by fingernail)
Impression
possible
Very light
impression
possible
Impression not
possible
Impression not
possible
Impression easily
poduced
Special features Smears when
sawn
Floats in water Yes Yes No No Yes
Notch sensitivity No Slight Yes Yes Yes
Weather resistance Stabilised, good Stabilised, good Stabilised, good Stabilised, good Stabilised, good
Method of
permanent joining
Fusion Fusion Solvent cement Solvent cement Fusion
Suitable fo
mechanical jointing
Yes Yes Yes Yes Yes
Stress crack
sensitivity with
regard to jointing
with save media,
e.g water
Some Slight None None None