Flammable/Pyrophoric Materials - Edwards GXS Series Instruction Manual

connection (at the standard pressure switch or the option flow meter). Nitrogen and
clean dry air are suitable purge gases for the dry pumping systems. To use a different
purge gas, please contact us.
Check visually that the dial pressure gauge and rotameter (if installed) is not damaged
when installing the dry pumping system.
Note:
Refer to

3.4.1 Flammable/pyrophoric materials

WARNING:
Obey the instructions and take note of any precautions given below to ensure that
pumped gases do not enter their flammable ranges.
When flammable or pyrophoric materials are present within the pump there may be
additional risks that the user is responsible for assessing and managing as part of the
entire process system installation. The severity of the risks and the necessary control
measures will depend largely on whether the process system exhaust is in the
flammable region, if this is part of normal operation, or if it might only occur under rare
conditions. The additional risks arise because all dry pumps must be considered as
potential source of ignition due to the heat of compression, or possibly friction. If
ignition occurs then the following may happen:
▪ High pressures could occur within the pump and may not be contained.
▪ A flame front could travel back up the foreline.
▪ A flame front could travel downstream from the exhaust of the pump.
Industry best practice suggests that the following measures will reduce the risks of
pumping flammable mixtures and pyrophoric materials, but it is the responsibility of the
user to carry out a risk assessment and take appropriate measures:
▪ Do not allow air to enter the equipment.
▪ Ensure that the dry pumping system is leak‑tight.
▪ Ensure that gases in the pump do not enter the flammable range. This may be
achieved by diluting gases in the pump by supplying sufficient inert gas purge. For
example, dilution with nitrogen to below one quarter Lower Explosive Limit (LEL)
or, if that is not practical, to below 60% Limiting Oxidant Concentration (LOC).
▪ The gas module supplied with the pump is not intended to perform a safety
function. Users may need to consider adding appropriate measures to monitor the
flow of purge gas (for example, external sensors). The dry pumping systems that
are fitted with light‑duty gas module must not be used on applications pumping
flammable or pyrophoric materials.
For further information please refer to publication number P40040100, applications
note 'Pumping Flammable Gases' P4100090 or contact us.
M58800880_H - Installation
Purge data on page 18 for the purge gas supply requirements.
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