Eskom Holdings
Southern Region
FINAL DESIGN PACKAGE
VOLUME 1: DETAIL DESIGN
Project Name
Mbashe Hydro Refurbishment:
Refurbishment of 4 x Main Isolation Valves (MIVs)
Project Number
4600046481/NDS00234
Revision
0
PS5
VALVES
CONTENTS
PS5 1
PS5 2
PS5 3
GATE VALVES
PAINTING OF VALVES
PAYMENT
PS5 1
GATE VALVES
Gate valves shall comply with SABS 664 waterworks pattern wedge gate valves of the
types, classes and sizes listed in the Schedule of Quantities and shall be provided with
the following:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
Double Flanged
Non-rising spindles
Handwheels with the direction of rotation to close and open marked thereon (except
where scheduled to be provided with caps).
The direction of rotation for closing the valve shall be clockwise when viewed from
the top. The direction of opening or closing each valve and the appropriate words
shall be embossed on the cap and superfluous arrow heads shall be completely
ground off the castings.
Type B gunmetal trim.
The facility to permit repacking of the gland whilst the valve is under pressure.
The valves shall be subjected to the "closed end" test, the "open end" test and the
working pressure test. The test pressure for the open end tests shall be one and half
times the rated working pressure of the valves, and for the body twice the rated
working pressure. The working pressure test shall be carried out as an open end
test. There shall be no leakage under any of the above test conditions.
Each gate valve shall be capable of being opened and closed by one man using a
tee key when the unbalanced head on the gate is equal to the open end test
pressure. The total effort required to operate the valve shall not exceed 400 N
(representing a simultaneous push/pull of 200 N) on the ends of a tee key 900 mm
long.
Except where otherwise stated, the flanges are to be in accordance with and drilled
off-centre to SABS 1123 or as scheduled. The non-rising spindle shall be bronze or
stainless steel and the spindle nut either bronze or gun metal.
A complete specification, accompanied by drawings, is to be submitted at the time of
tendering. Rates for all the gate valves shall include for testing and supply of test
certificates, copies of which shall be attached to each relevant invoice and to each
relevant invoice and to each copy of each invoice. The open end test pressure shall
be stamped on the top of one flange of each valve. No payment will be made for
valves unless the test certificates have been submitted. Valves not complying with
SABS 664 will be considered as an alternative offer provided full technical details are
submitted with the tender.
After completion of the factory tests, all valves shall be thoroughly cleaned and painted
in accordance with Clause 6 of this Specification.
PS5 2
PAINTING OF VALVES
PS5 2.1
The cleaning and painting of valves as specified hereunder is to be carried out at the
factory prior to despatch to site.
16-C3.8.5_PS5_Valves.doc
PS5.1
Eskom Holdings
Southern Region
FINAL DESIGN PACKAGE
VOLUME 1: DETAIL DESIGN
Project Name
Mbashe Hydro Refurbishment:
Refurbishment of 4 x Main Isolation Valves (MIVs)
Project Number
4600046481/NDS00234
Revision
0
PS5 2.2
All cast iron surfaces of every valve shall be prepared for painting to a thoroughly clean
condition free of all grease and deleterious matter. Steel surfaces shall be prepared in
accordance with Swedish Standard SIS 05 5900 for a Sa 2.5 finish.
PS5 2.3
Internal surfaces shall then be treated with two coats of Copon Hicote 151E or other
approved non-toxic epoxy resin paint to give a total minimum dry film thickness of 160
micrometres; both coats being applied within 48 hours of commencement of painting.
PS5 2.4
External surfaces shall, immediately after cleaning, be treated with one of the following
alternative paint systems:
(a)
System 1 - for valves situated in underground chambers or exposed conditions.
Apply three coats of an approved epoxy coal tar paint to give a minimum total dry film
thickness of 240 micrometres; all three coats being applied within 72 hours of
commencing the first coat.
(b)
System 2 - for valves situated in pump stations etc.
Apply one coat of zinc chromate primer followed by one coat of undercoat tinted where
necessary, and a final coat of best quality gloss enamel. The total dry film thickness of
the system shall be not less than 200 micrometres.
PS5 2.5
Non-ferrous metal or stainless steel surfaces shall not be painted.
PS5 2.6
After erection on site all valves shall be cleaned and the paint work refurbished where
necessary to restore the condition to that at the time of leaving the factory.
PS5 3
PAYMENT
The price quoted for all valves is to include for independent factory testing of valves.
16-C3.8.5_PS5_Valves.doc
PS5.2