SPECIFICATION FOR SURGE VESSEL AND
AIR COMPRESSOR
Revised on 30-07-2018
TABLE OF CONTENTS
1.0
Specification For Surge Vessel And Air Compressor
6aj-2
1.1
General
6aj-2
1.1.1 Scope
6aj-2
1.1.2 Type
6aj-2
1.1.3 Quality Assurance
6aj-2
1.2
Vessel
6aj-3
1.2.1 Vessel Design
6aj-3
1.2.2 Painting
6aj-3
1.2.3 Fittings and Instruments
6aj-3
1.3
6aj-4
Factory Testing
1.3.1 Materials
6aj-4
1.3.2 Hydraulic Test
6aj-4
1.3.3 Performance Test
6aj-4
1.4
6aj-4
Vertically Mounted Surge Vessel for ………. Pumping Mains
1.4.1 Surge Vessel
6aj-4
1.4.2
Slow Closer Non Retain Valve
6aj-5
1.5
Specifications for Air Compressor
6aj-5
1.5.1 Scope
6aj-5
1.5.2 Design
6aj-5
QUESTIONER
1
Surge Vessel For ………
6aj-6
2
Air Compressor ………
6aj-7
NWSDB/ Specification for Surge Vessels & Air Compressor
CAPC : MPC : DPC : PPC : RPC :- June 2013
6aj-1
1.0
SPECIFICATION FOR SURGE VESSEL AND AIR COMPRESSOR
1.1
GENERAL
1.1.1 Scope
The Surge Vessel shall be installed at the ……………………………………. to protect
the pumping main from the adverse affects of the water hammer when trip off the pumps
due to the power failures or sudden stoppage of the pump.
The Surge Vessel shall consist of a vertical steel tank, enclosed bladder, compressor
(optional), connection valve, pipes and all necessary appurtenances to arrest surges in
water pumping main. The Supplier shall require that the surge vessel specified herein be
supplied by a single manufacturer.
The supply and services include:
•
Design of the surge vessel
•
Supply of surge vessel/s as described below
•
Installation of the surge vessel
•
Construction of suitable concrete base for the surge vessel
•
Supply and installation of necessary pipes and fittings, valves etc.,
necessary for smooth function of the surge vessel.
1.1.2 Type
Surge vessel shall be of air pressured vertical, bladder type suitable for open-air
installation, subject to the condition that vessel capacity shall not be less than volume
specified in the particular specifications. If there is any deviation in vessel capacity,
details of the surge analysis calculations shall be submitted. For this calculation the
contractor can obtain the basic data from the given pump specifications and detail
drawings attached herewith. Also the detailed drawings showing materials of
construction shall be submitted to the Engineer before fabrication of the vessel.
1.1.3 Quality Assurance
The surge vessel manufacturer shall be certified according to the relevant authority (BSI,
ISO etc.) for the manufacturing facility of the surge vessel. Also he is responsible for
obtaining the necessary approvals from the relevant authorities for legal operation on the
Site under the ruling conditions of operation.
Total Quality Assurance system shall comply with ISO BS 5750, ISO 9001 or 9002
series/BS EN ISO 9001 or 9002 series or an equivalent acceptable to the Engineer.
The certificates valid for current production (years ……/……) shall be produced with
the offer. Surge vessel to be supplied under this contract shall only be from the approved
factory location.
NWSDB/ Specification for Surge Vessels & Air Compressor
CAPC : MPC : DPC : PPC : RPC :- June 2013
6aj-2
Revised on 30-07-2018
1.2
VESSEL
1.2.1 Vessel Design
The surge vessel shall be made of welded steel shells and dome ends according to BS
1501 Part 1 or equivalent. The volume of the tank and operating pressure shall be
complying with the particular specification or according the calculation given by the
supplier if deviation occurred. The vessel shall be provided with a manhole access and a
drainage system.
The vessel shall be of vertical type and mounted on legs.
The vessel shall be provided with all necessary pipe works, valves etc., and connections,
tapping points for instrumentation, vents and drains and a pressure gauge.
The vessel shall be protected with a safety valve and volume of vessel shall not be less
than 1 m3.
The Surge vessel shall be designed for anchor bolting to a concrete foundation. The
supports shall be designed to with stand all natural loadings, any hydraulic and
pneumatic thrusts resulting from surges.
1.2.2 Painting
The surge vessel shall be painted as indicated below:
•
Internal coating – Food quality epoxy paint approved by paint manufacture with a 10 year
warranty.
•
External coating – 3 coats of epoxy, approved by a paint manufacturer with a 10 year
warranty.
•
External coating colour-Shall be Sky Blue
1.2.3 Bladder
The bladder shall be made out of butyl and shall be easily replaceable. It shall be suitable
and approved for use in drinking water systems. The bladder shall be perfectly watertight
and airtight after the installation inside the vessel.
1.2.4 Fittings and Instruments
The surge vessel shall be equipped with the following:
•
Flange outlets
•
Inspection hole
•
Drainage plug
•
Glass tube levels indictor with an isolating valves
•
Pressure gauge with isolating valve
•
Safety valve
•
Air inflation plug
•
Supporting legs
NWSDB/ Specification for Surge Vessels & Air Compressor
CAPC : MPC : DPC : PPC : RPC :- June 2013
6aj-3
1.3
•
Lifting lugs
•
Air Compressor (optional)
•
Sluice valves with necessary by pass arrangement with orifice plate to
cater return wave if necessary.
•
Non return vales with slow closing arrangement.
FACTORY TESTING
1.3.1 Materials
Strength tests of the steel, Butyl and welded joints of the surge vessel shall be performed
in accordance with the applicable standards. The Supplier shall furnish the Engineer with
certified copies of the results of all tests along with the standards.
1.3.2 Hydraulic Test
The surge vessel shall be hydrostatically tested at 1.5 times the maximum working
pressure for not less than 60 minutes.
During the test, the vessal should not show any undue deflection, signs of weakness at
any point or leaks through welded joints/ gaskets or other defects.
The Supplier shall furnish the certified copy of test results to the Engineer.
1.3.3 Performance Test
The surge vessel shall be factory tested for its performance. The supplier shall submit the
test results before shipment of the vessel.
1.4
VERTICALLY MOUNTED SURGE VESSEL FOR ………………. PUMPING
MAINS
1.4.1 Surge Vessel
The supplier shall submit all the calculations if necessary and details related to the above
surge vessel as per the specifications
The surge vessel is to be installed as shown on the drawings.
Description
Unit
Surge vessel at ………..
Maximum vessel capacity
m3
………….
Base plate coefficient
………….
The allowable pressure range Minimum
in the pipe line
Maximum
-0.6
………….
Particle size expected
………….
The vessel shall be designed to maintain the pipeline pressure within the range
mentioned above.
NWSDB/ Specification for Surge Vessels & Air Compressor
CAPC : MPC : DPC : PPC : RPC :- June 2013
6aj-4
For basic data required for surge analysis, please refer data given under pump
specification and the Drawing.
1.4.2
Slow Closer Non retain valve
The Slow Closer Non Retaining Valve shall be of free acting type specially designed for
use in pumping main in between pump and Surge Vessel, giving slow closing as
specified below and low head loss characteristic when this valve is in the open position.
The Valve shall be Gunmetal or Bronze alloy door seating with the access cover of
adequate dimension for removal of door when necessary.
Description
Units
Closing Time
….
……..Seconds
Slow Closer Non retain valve
1.5
SPECIFICATIONS FOR AIR COMPRESSOR
(This equipment may not be purchased under this contract, if a suitable air compressor
is available for feeding air to the surge tank in a event of drop in air pressure inside the
tank.)
1.5.1 Scope
The compressor shall be integrated units with vertical or horizontal tank and piston
compressor aggregate mounted on the top and total product should be confirmed to
ISO/BS standards.
The compressor shall be compatible with the surge vessel specification, to create
necessary pressure requirement of the above surge vessel.
1.5.2 Design
The compressor unit shall be protected against corrosion.
The unit shall be equipped with: oil separator for oil free outlet of compressed air,
pressure regulator, and suction filter, automatic pressure control of start and stop of the
compressor aggregate, line circuit breaker and water trap.
Mains supply
: 400 VAC, 3 Ph, 50 Hz
Starting method
: DOL (Direct On-Line)
Maximum allowed noise pressure
: 85 dB @ 1m.
The compressor with tank may be regarded as pressure vessel and thus they shall be
supplied with approval for operation in Sri Lanka from the relevant authorities.
Type
Reciprocating type, with squirrel cage,
three phase induction motor
NWSDB/ Specification for Surge Vessels & Air Compressor
CAPC : MPC : DPC : PPC : RPC :- June 2013
Capacity
(lit)
Maximum
pressure/(bar)
50 -100
10
6aj-5
Type of
connection
Flexible Hose up
to connection
QUESTIONER
1. Surge Vessel For ……………………………………………
1
Make
&
Manufacture
Country
of
2
Name
and
address
Manufacturer’s factory
of
E-mail Address
Fax/Tel
3
Type
4
Model
5
Volume of the cylinder (m3)
6
Standard to which the Surge
Vassal is Manufactured
7
Maximum Working Pressure
8
Maximum and minimum
surge pressure of the pumping
main with out the surge vassal
*
9
Maximum and minimum
surge pressure of the pumping
system with the surge vassal
operation *
10 Material of construction
a. Vessal
b. Bladder
11 Are
all
instruments
available
fittings
and
specified
12 Indicate quality of painting
a Internal
b External
13 Operating principle
14 Adjustable Range
*
This required if Surge Vassal design by the contractor
NWSDB/ Specification for Surge Vessels & Air Compressor
CAPC : MPC : DPC : PPC : RPC :- June 2013
6aj-6
2.
Air Compressor……………………………………………
1
Make
&
Manufacture
Country
of
2
Name
and
address
Manufacturer’s factory
of
E-mail Address
Fax/Tel
3
Type
4
Model
5
Capacity (m3/hr)
6
Delivery pressure m / bar
7
Casing Material
8
Speed RPM
9
Noise Level dB
NWSDB/ Specification for Surge Vessels & Air Compressor
CAPC : MPC : DPC : PPC : RPC :- June 2013
6aj-7