Sentinel Performance Solutions Ltd, The Heath Business & Technical Park
Runcorn, Cheshire, WA7 4QX T: +44 (0) 1928 588330
F: +44 (0) 01928 588368
Page 4 of 4
june-10
Technical Information
* Frost Protection
Please note that the frost protection figure quoted
in the Test Kit instructions refers to a ‘burst
protection’ at which propylene glycol
concentration is sufficient to prevent bursting of
pipework but not necessarily high enough to
maintain the fluid in a pumpable state. This figure
is the ‘Setting Point’ as measured using the DIN
51583 method. The ‘Setting Point’ is the
temperature at which the fluid solidifies.
The temperature figure read from the
refractometer corresponding to the percentage
glycol figure is the onset of the freezing point as
measured using the ASTM D1177 method. For a
propylene glycol/water mixture, at temperatures
between its ‘Freezing Point’ and its ‘Setting
Point’, the mixture becomes progressively more
difficult to pump. A comparison chart of ‘Freezing
Point’ and ‘Setting Point’ for propylene
glycol/water mixtures is shown below.
% Propylene Glycol (v/v)
0
5
10
15
20
25
30
35
40
45
50
Freezing Point (
°
C)
0
-2
-4
-6
-8
-11
-13
-17
-21
-27
-34
Setting Point (
°
C)
0
-2
-5
-8
-10
-14
-17
-22
-28
-37
-50
