MHP-TN USER INSTRUCTIONS ENGLISH 71576313 - 02/07
Page 7 of 28
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1.6.4.2 Marking
An example of ATEX equipment marking is shown
below. The actual classification of the pump will be
engraved on the nameplate.
II 2 GD c IIC 135 ºC (T4)
Equipment Group
I = Mining
II = Non-mining
Category
2 or M2 = High level protection
3 = normal level of protection
Gas and/or Dust
G = Gas; D= Dust
c = Constructional safety
(in accordance with EN 13463-5)
Gas Group (Equipment Category 2 only)
IIA – Propane (typical)
IIB – Ethylene (typical)
IIC – Hydrogen (typical)
Maximum surface temperature (Temperature Class)
(see section 1.6.4.3)
1.6.4.3 Avoiding excessive surface temperatures
ENSURE THE EQUIPMENT TEMPERATURE
CLASS IS SUITABLE FOR THE HAZARD ZONE
Pumps have a temperature class as stated in the
ATEX Ex rating on the nameplate. These are based
on a maximum ambient of 40 °C (104 °F); refer to
Flowserve for higher ambient temperatures.
The surface temperature on the pump is influenced
by the temperature of the liquid handled. The
maximum permissible liquid temperature depends on
the temperature class and must not exceed the
values in the table that follows.
The temperature rise at the seals, bearings and due
to the minimum permitted flow rate is taken into
account in the temperatures stated.
Temperature
class to
EN 13463-1
Maximum
surface
temperature
permitted
Temperature limit of liquid
handled (* depending on
material and construction
variant - check which is
lower)
T6
T5
T4
T3
T2
T1
85 °C (185 °F)
100 °C (212 °F)
135 °C (275 °F)
200 °C (392 °F)
300 °C (572 °F)
450 °C (842 °F)
Consult Flowserve
Consult Flowserve
115 °C (239 °F) *
180 °C (356 °F) *
275 °C (527 °F) *
400 °C (752 °F) *
The responsibility for compliance with the
specified maximum liquid temperature is with the
plant operator.
Temperature classification “Tx” is used when the
liquid temperature varies and the pump could be
installed in different hazardous atmospheres. In this
case the user is responsible for ensuring that the
pump surface temperature does not exceed that
permitted in the particular hazardous atmosphere.
If an explosive atmosphere exists during the
installation, do not attempt to check the direction of
rotation by starting the pump unfilled. Even a short
run time may give a high temperature resulting from
contact between rotating and stationary components.
Furthermore, confinement of liquid in the pump and
pipes must be avoided (valve closed). If the liquid
heats up this may cause excessive pressure and
lead to bursting of pump components.
Where there is any risk of the pump being run against
a closed valve generating high liquid and casing
external surface temperatures it is recommended that
users fit an external surface temperature protection
device.
Avoid mechanical, hydraulic or electrical overload by
using motor overload trips, temperature monitor or a
power monitor and make routine vibration monitoring
checks.
In dirty or dusty environments, regular checks must
be made and dirt removed from areas around close
clearances, bearing housings and motors.
1.6.4.4 Preventing the build up of explosive
mixtures
ENSURE PUMP IS PROPERLY FILLED AND
VENTED AND DOES NOT RUN DRY.
Ensure pump and relevant suction and discharge
pipeline system is totally filled with liquid at all times
during the pump operation, so that an explosive
atmosphere is prevented. In addition it is essential to
make sure that seal chambers, auxiliary shaft seal
systems and any heating and cooling systems are
properly filled.
If the operation of the system cannot avoid this
condition the fitting of an appropriate dry run
protection device is recommended (eg liquid
detection or power monitor).
To avoid potential hazards from fugitive emissions of
vapor or gas to atmosphere the surrounding area
must be well ventilated.
