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Your Ref :

our Ref ' WSN 92413 I 46Date = 22 Nov 2012

Please address all correspondence to Water Supply (Network) Depanment

rer : 67313669 Fax , 67313023Email : christopher_chua@pub.gov.sg

To all Relevant Government Agencies,M&E Consultants, Associations andPlumbers & Suppliers of Water Fittings

Statutory Boards, Professional Engineers,Organisations, Licensed Water Service

Dear Sir/Madam

USE OF PILOT OPERATED BALL FLOAT VALVES FOR POTABLEWATER STORAGE TANKS

I refer to our circular dated 18 Apr 12 informing of the discontinuation ofthe use of pilot operated ball float valves for potable water storage tanks. In thecircular, we inforrned that potable water storage tanks fitted with pilot operated ballfloat valves that have a small opening (25 - 50 mm diameter) to accommodate therod connecting the float inside the tanks and the control mechanism above the tanksare not allowed to be installed for new and existing potable water storage tanks, asthe openings cannot be effectively sealed.

2 We have since received several feedback from Professional Engineers,Licensed Water Service Plumbers and suppliers. We have considered thesefeedback and have decided to flrne-tune and review our requirements to allow forthe installation of pilot operated ball float valves for potable water storage tanksunder the following conditions:

(a) Projects/Works with pilot operated ball float valves for potable waterstoraee tanks installed/procured on or before 1.8 Apr 12 for whichCertificate of Satisfactory Completion has yet to be submitted

Professional Engineers and Licensed Water Service Plumbers shallensure that the potable water storage tanks are well guarded against:

i any securitybreach; and

ii ingress of undesirable elements such as rainwater, animals,insects, foreign material, etc

by using either an appropriate valve or by retrofitting the pilot controlmechanisms/valves of the pilot operated ball float valves installed

40 Scotts Road #22-O1 Environment Building Singapore 228231 Republic of SingaporeTel: 62358888 Fax: 67313020 Website: www.pub.gov.sg

outside of the potable water storage tanks such that the water tanks donot have any holes or resulting holes, if any, are completelysealed/secured with fixed joinVfittingladaptor (please refer toAnnex A for some of the designs of pilot operated ball float valvesallowed for potable water storage tanks). Professional Engineers andLicensed Water Service Plumbers shall also ensure that the pilotoperated ball float valves installed/procured for their projects havebeen tested to meet the Standards and requirements stipulated byPUB for such valves.

(b) Projects/Works with pilot operated ball float valves for potable waterstorase tanks installed/procured or to be installed/procured after 18Apr 12

The pilot operated ball float valves for potable water storage tanksmust meet the following requirements:

i The entire pilot operated ball float valve shall be installed withinthe potable water storage tank; or

ii Where all components of the pilot operated ball float valves withthe exception of the main valve/body are installed within thepotable water storage tanks, any opening in the tank linking thecomponents within the tank to the main valve/body shall becompletely secured/sealed with fixed joint/fitting/adaptor.

In addition, the pilot operated ball float valves must be tested to meetthe Standards and requirements stipulated by PUB for such valves.

3 For projects/works with pilot operated ball float valves for potable waterstorage tanks installed/procured on or before 18 Apr 12 for which Certificate ofSatisfactory Completion has already been submitted, PUB will be writing to theProfessional Engineers/Licensed Water Service Plumbers/MCSTs/building ownersseparately for rectification works.

4 We will appreciate it very much if you can help to disseminate the contentsof this circular to the relevant officers/members in your company/organisation andensure that the requirements in Para 2 are strictly complied with in all of yourprojects involving pilot operated ball float valves for potable water storage tanks.

5 We wish to reiterate again that the Public Utilities (Water Supply)Regulations and Singapore Standard CP 48: Code of Practice for Water Servicesstate clearly that every potable water storage tank shall be watertight and shall be soequipped to be secured against unauthorised access, contamination and pollution ofthe water contained therein. Please note that non-compliance with the above

requirements is an offence under the Public Utilities (Water Suppl9 Regulationsand PUB will not hesitate to take stern action against anyone found not complyingwith the above requirements.

6 If you have any queries concerning this circular or need any furtherclarification, please do not hesitate to contact any of the following PUB officerslisted below.

Name Email Contact NoMr Christopher Chua chri s tophe r _chua@pub . gov. s g 67313669

Mr Lee Cai Jie lee_caij ie@pub. gov. s g 673132s0

Mr R Rajendram raj endram_m_r amas anty @pub . gov. s g 673r38s9

Mr Tow Chuan Kwee tow-chuan_kw ee@pub . gov. s g 68852447

Yours faithfully

WilCHRISTOPHER CHUAPRINCIPAL ENGINEER (INSPECTORATE)for DIRECTORWATER SUPPLY (NETWORK) DEPARTMENT

Enc

Annex A

a) Some possible designs of p i lot control valve/mechanism for use inpotable water tank - Entire pilot f loat-operated valve or allcomponents of the pilot float-operated valve (with the exception ofthe main valve/body) is installed within the potable water tank

Design (C)

Design (B)

Design (D)

Pipe trr Brllf loat i l l re

Pipe to Ballfloat valve

Design (E) Design (F)

b) Some possible design modif icat ions of p i lot control valve/mechanism for usein potable water tank - (only for those supplied / installed before 18 Apr 121

Design (A) Design (B)