MSA 47K Series User Manual

GB
MAINTENANCE AND SERVICE MSA
18 Series 47K Gas Detector [SIL 2]
5.3. Series 47K-PRP and Series 47K-HT-PRP
For the gases or vapours shown in the tables of Section 5.3.1 and 5.3.2 the
response curves have been tested according to EN 61779-1. If the LEL of a
substance was not listed in EN 61779-1, the LEL has been taken from the
Chemsafe data base [Dechema, Frankfurt]. Due to legal requirements other
locally used LEL values might be mandatory.
It is highly recommended that the gas detector is exposed to clean air when
calibrating the zero and a mixture of the target gas in air with a concentration of
approximately 50% LEL.
If calibration with the target gas is not possible a reference calibration can be
performed with 0,85 vol% Propane C
3
H
8
in air and using the relative response
data given in the table of Section 5.3.1 and 5.3.2. These values are only valid for
new sensors and, unless otherwise stated, they refer to an ambient temperature
of 20 °C. If using a reference gas to calibrate the gas detector the displayed
values may vary by up to ±20% from the target gas concentration.
Reference calibration example for 50% Acetone:
(1) Relative response factor for Acetone from = 0.94
table in Section 5.3.2.
(2) Propane calibration gas concentration being used = 0.89 vol% C
3
H
8
(3) Propane volume concentration for 100% LEL = 1.7 vol%
(4) Propane calibration gas concentration in % LEL
= 52.4% LEL
(5) Gas detector span setting = 52.4% LEL x 0.94 = 49.3% LEL
= 0.89 vol% C
3
H
8
x
100% LEL
1.7 vol% C
3
H
8

MSA 47K Series Specifications

General

Brand	MSA
Model	47K Series
Category	Gas Detectors
Language	English