－18－
pipe misalignment error, pipe expansion, ground subsidence;
4.
The suction pipe shall meet the net positive suction head (NPSH) required by the pump,
and the pipe shall be as short as possible with little turning. When the pipe length
exceeds the distance between the equipment and the pump, the process system shall be
requested to calculate.
5.
No airbag in suction pipe;
6.
Except the centrifugal fire pumps (vertical shaft,turbine type),other fire pumps must be
water supply at positive pressure.
I.
Improper installation of eccentric reducing pipe at pump suction, see “figure A.3.3.1.1”;
FIGURE A.3.3.1.1
II.
Correct installation of eccentric reducing pipe at pump suction, see “figure A.3.3.1.2”;
FIGURE A.3.3.1.2
Eccentric reducing pipe
Suction
Pipeline
Eccentric reducing pipe
Airbag
Suction
Pipeline