2.2.2.2
Runaway Speed
The pump shall be designed to sustain full runaway speed without damage at
maximum head difference across the pump. Based on the system design as
shown by the drawings the manufacturer shall compute the maximum reverse
runaway speed, and the pump and motor shall be designed to sustain that
reverse rotation without damage.
2.2.3
Pump Construction
2.2.3.1
General
The major pump components shall be of materials as described in Table 1.
The entire support assembly shall be designed in accordance with Sections
13080 SEISMIC PROTECTION FOR MISCELLANEOUS EQUIPMENT and 15070A SEISMIC
PROTECTION FOR MECHANICAL EQUIPMENT. All the exposed nuts and bolts shall
be stainless steel. All mating surfaces where watertight sealing is
required shall be machined and fitted with nitrile rubber O-rings. The
fitting shall be such that the sealing is accomplished by metal-metal
contact between machined surfaces which results in controlled compression
of the O-rings. Sealing compounds, grease, or secondary devices are not
acceptable.
2.2.3.2
Pump Lifting Handle And Lifting Lugs
The lifting handle shall be designed to bear the entire weight of the
pumping unit at a conservative factor of safety. Lifting lugs shall be
provided where the weight of the separate part requires a lug. The
contractor shall follow the manufacturers recommendations for handling of
the pump.
2.2.3.3
Pump and Motor Bearing Arrangement
The pump and motor bearings shall be the standard design of the
manufacturer for the pump supplied under this specification. The type and
number shall be of proven design as used in previous operating units
supplied by the manufacturer. The bearings shall be of the grease
lubricated and sealed type. The bearings shall have a minimum B-10 bearing
life of 50,000 hr. Each bearing shall be of the correct design to resist
the radial and thrust loads applied. Enough bearings shall be provided to
ensure the pump rotating elements are supported so that the possibility of
excessive vibration is eliminated. Ball and roller bearings life and load
ratings shall conform to ABMA 9 and ABMA 11.
2.2.3.4
Mechanical Seals
A mechanical rotating shaft seal system shall be provided between the
impeller and motor to ensure the motor housing seal. The mechanical seals
shall be in tandem, lapped and face type seals running in lubricant
reservoirs for cooling and lubrication. The mechanical seals shall contain
both stationary and rotating tungsten carbide face rings unless otherwise
specified. In order to avoid seal failure from sticking, clogging, and
misalignment from elements contained in the mixed media, only the seal
faces of the outer seal assembly and its retaining clips shall be exposed
to the mixed media. All other components shall be contained in the
lubricant housing. All seal faces must be solid material capable of being
relapped. The seals shall require neither maintenance nor adjustment, but
shall be easy to check and replace. Shaft seals without positively driven
SECTION 15132A
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