Test method to determine the characteristic rate of discharge for plumbing fixtures and devices

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Test method to determine the characteristic rate of discharge for

plumbing fixtures and devices

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'I'EST METHOD r8 DETERbiINE THE Ctt4MCTER ISTIC IlATli 01: DISCIIARGI; FOR

PLUMBING

FIXTURES AND DEi'ICES

by R.K. Beach

SCOPE

This t e s t method describes a procedure to determine t h e c t ~ a r a c t e r i s t i c

r a t e o f discharge f o r plumbing fixtures and devices.

Tests _may_{be carried}_{o u t}_{u s i n g}_{t h e}_apparatus_and_{p i p i n g}_{shown in}

Figures 1 and 2 . _An _{arrangement o t h e r t h a n}_{t h a t}_shown

_in

_Figure₁_may _be

used if it can be proven that t h e change will not i n f l u e n c e t h e r e s u l t s . T h i s procedure assumes t h a t t h e s t r i p c h a r t r e c o r d will b e p r o c e s s e d manually to produce rhc characterisric r a t e o f d i s c h a r g e curve f o r t h e Eixturc o r device. '10 facilitate t h i s t h e total deflection s h o u l d exceed

50 per cent of the c h a r t width and she combination o f t h e chart speed and t h e f u l l scale deflection chosen should b e such t h a t the s t r i p c h a r t record has a maximum slope of about 4 5 " . As the expected maximum rate of d i s c h a r g e

i s 4 L / s , t h e product of _{thc s t r i p c l ~ a r t ' s}_{scale f a c t o r}_and_{c h a r t}_speed should a l s o h e 4 L / s . A c l e a r p l a s t i c rate o f discharge template, sl~own i n

Figure 3 , is used to process the s t r i p c h a r t r e c o r d . Users w i l l f i n d it

more convenient t o replace t h e slope scale with a rate o f discharge s c a l e s o t h a t t h e r a t e of discharge can b e read o f f directly. The r a t e o f d i s c h a r ~ e s c a l e fs t h c p r o d u c t o f the s l o p e times t h e scale f a c t o r in

L/mm

times t h e c h a r t speed in m / s .

The f i x t u r e p i p i n g shown i n F i g u r e 2 should be p l a s t i c and s h o u l d conform t o t h e a p p r o p r i a t e standard i n t h e Canadian Standards Association B181 series o f standards. 1)imensions n o t specified should be tho minin~um p r a c t i c a l . P i p i n g need not he s o l v e n t welded b u t should b e s e a l e d .

'Ftic prcssurc i n t h e water supply systcrn u n d e r no flow conditions s h o u l d I)c atljusted to f ; ~ l l w i t h i n the 275 to _{425 KPa} _{(40 to 6 0}_psi)_{r a n g e ,} 'Thc ~ ~ r c s s u r c in t h e watcr supply line d u r i n g t h e t e s t i n g o f a f i x t u r e t h a t

rcquircs a supply o f water f o r i t s normal and proper functioning s h o u l d conform t o t h e requirements of t h e Canadian Plumbing Code e x c e p t that,

where a manufacturer s p e c i f i e s t h a t a higher pressure is r e q u i r e d , t h e higher flow 2ressure s h o u l d be used.

CALI BWTI OK

The complete t e s t s c t up should b e t e s t e d f o r a straight line rclation-

s h i p a n d , wherc necessary, modifications should be made to ensure t h a t t h e variation hetween t h e a c t u a l capacity of t h e tank and that recorded h y t h e s t r i p chart does n o t vary by mare than

*

2 per cent.

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A t _thc_{b c g i n n i ~ l g}_{o f} _ciicl~_st*rir8s_{o f}_t_{c s t s}iincl whcncvcr t h c r;irlgc o f t h e s t r i p chart I-CCOTC! is ch:111s~-il

,

t11ll st r i 1) c11;t rt i,ccil~-rlcl- sllou 14

be c a l i h r a t cd by f i.wt zcroin:: t31c 1)cn tl~erl ing :i ~i~cnswrcd clu:i~lt i t y of wxter t t , t h e tank a n d a d j u s t i n g t h e s c a l c r r n d i ~ l g .

TEST LOADS

(a] :I f i x t u r e with an overflow s h o u l d be f i l l e d t o t h e overflow.

[ b ) !If i x t u r e withnut a n o v e r f l o w should be filled t o a h e i g h t c y u a l to 7'; pcs cent o f the vertical distance between t h e bottom of t h e fixture ant1 i t s f l o o d l e v e l rim.

LC) 11 f l u s h t a n k t y p e f i x t u r e s h o u l d have t h e r c f i l l mechanism adjusted t o f i l l t h e tank t o t h e Level mark r n d i c a t e d by t h e manufacturer

and, where applicable, the fixzure should b e filled by operating the

f l u s h i n g mechanism.

( d ) ,Any o t h e r d e v i c e o r appliance should be filled to a l e v e l t h a t

represents a l a r g e b u t n o t improbable load.

( a ) A fixture t h a t h a s an overflow s h o u l d havc i t s r a t e of d i s c h a r g c determined w i t h t h e overflow open and again with ~t sealed.

(b) A fixture t h a t h a s t w o o r more compartments s h o u l d have its

rate of discharge determined using The compartment t h a t experience o r 1 1 r e k i m i n a r y t e s t i n g indicates will produce t h e highest peak r a t e of d i s - charge and determined again by d i s c h a r g i n g all compartments together.

(c) A f i x t u r e t h a t i s p r o v i d e d w i t h a removable strainer ( e - g . , t h e

crumb cup of a kitchen sink) sllould have its r a t e d discharge d e t e r m i n e d

without the strainer and again by o p e n i n g it in place.

[dl 11 fixture t h a t requires a flushometer f o r i t s p r o p e r functioning

s h o u I d have its rate o f discharge determined under two c o n t l i t i o n s : w i t h the flushometer as received from t h e manufacturer and a g a i n as a d j u s t e d t o discharge t h e maximum amount o f water. The flushometer should R e supplied w i t h t h e f i x t u r e .

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Each test s h o u l d be repeated t h r e e times except that f o r t l ~ o s e fixtures that are provided w i t 1 1 a f l u s h i n g mechanism o r t h a t discharge

less than 1 0 l i t r c s o f water, each test s h o u l d be repeated f i v e times. TEST PROCEDURE

Install t h e f i x t u r e o r device u s i n g the a p p r o p r i a t e piping arrzngement. Adjusc t h e Pressure Reducing Valve and flow resistor t o p r o v i d e thc correct

uatcr pressures. Preparc the fixture or device for testing by filling or Flushing i t . Drain t h e s c c c i v i n g t a n k i f required. A d j u s t t h e strip char-t:

rccordcr to t h e r e q u i r e d deflection s c a l e and specd and z e r o t h e pen,

S t a r t t l ~ c s t r i p c h a r t rccorder and clischarge t h e fixture or device by

a l ) c r ; ~ t l r ~ ~ tlic m c c h a t ~ i s m or removing t h e stopper. 'i'lre stopper s h o u l d h e ~ ~ u l l r d straight up each time i n order t o a v o i d g i v i n g t h e water a swirl as

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In t h e case of f i x t u r e whose f u n c t i o n i n g r e t ~ u i r e s t h c t r a p t o be

refilled, the strip chart r e c o r d e r may bp s t o p p e d a f t e r t h e innin f l u s h

has f i n i s h e d and he restarted b r i e f l y whcn tllc s u p p l y of water to e h c

f i x t u r e has stoppcd and thus recard the ; ~ c t u a l amount o f water t h a t was

discharged.

PROCESSING OF THE STRIP CHART RECORD

Draw a smooth curve through each of the s t r i p c h a r t records t o

average o u t t h e r a p i d fluctuations in pressure picked up by t h e t r a n s d u c e r .

Establish the zero point f o r time when t h e water f i r s t b e g i n s t o accumulate

i n the r e c e i v i n g t a n k -

S t a r t i n g from t h i s z e r o t i m e , r e a d o f f and tabulate f o r t h e same sclected times the t o t a l amount o f water discharged d u r i n g each t e s t r u n .

Thc selected time interval should n o r m a l l y be 1 s e c o n d , b u t s h o r t e r i n t e r v a l s

arc necessary at t h c beginning of the p e r i o d and may be needed when t h e rate

of discharge changes r a p i d l y .

Determine t h e average q u a n t i t y of water discharged and t h e time of

d i s c h a r g e by a v e r a g i n g the q u a n t i t y d i s c h a r g e d and t h e times when discharge ceased.

In

t h e case of water-closets and d e v i c e s w i t h Tray r e f i l l m e c h a n i s m > ,

t h e average discharge t i n w and t h e average q u a n t i t y d i s c h a r g e refcr to t h e

main f l u s h . Record a l s o the t o t a l discharge time and the t o t a l quantity o f

water discharged. The difference i n t h e quanitities discharged i s t h e trap refill l o s s . Average t h e amounts discharged f o r t h e _selected_times_and

t a b u l a t e . P l o t t h e r e s u l t s and draw a smooth c u r v e f a i r i n g it i n t o t e r m i n a t e h o r i z o n t a l l y a t t h e d i s c h a r g e t i m e .

By

means of t h e c l e a r p l a s t i c t e m p l a t e shown

in

_Figure₃_{determine t h e} rate o f d i s c h a r g e and corresponding t i m e o f discharge f o r s e v e r a l p o i n t s and tabulate. P l a t the r e s u l t s and draw i n a smooth c u r v e which is _{t h e}

characterisric s a t e _{o f d i s c h a r g e}_curve_Ear_{t h e f i x t u r e}_or_{d e v i c e .} _{T h e}_{d i s c h a r g c}

c u r v e o f 3 f i x t u ~ e w h o s e normal function r e q u i r e s refilling of the t r a p does

n o t i n c l u d e a n y subsequent trap refill loss.

C a l c u l a t e t h e mean rate o f flow equal t o the quantity discharged divided

by the time o f d i s c h a r g e . Determine t h e peak two-second mean r a t c o f d i s c h a r g e

which i s t h e h i g h e s t average r a t e of discharge of any two-second p e r i o d . Thc

accuracy of t h e characteristic discharge curve can be checked by comparing

the measured quantity of water discharged with the area under thc c u r v e . Complcte t h e Characteristic Discharge Rate Report.

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CIIARACTERI STIC RATti I)!: UISCtfrIlKII R131~UH'I'

[ I ] Device Tested ( 2 ) Mfr's Name

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Manufacturer

(43 h'ater pressure (a) S t a t i c KPa; (b) Flowing KP a

(63 P e r i o d o f Discharge s e c . ( 7 ) Quantity Discharged L

( 8 ) Mean r a t e of d i s c h a r g e L

(9) Peak 2 s e c . mean r a t e o f d i s c h a r g e L/ s

(103 Period o f Total Discharge s ec

( I I ) T o t a l quantity discharged L

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P R E 5 S U R E GAIJGE S H U T O F F P R E S S L ' R E R E D U C I N G VALVE RECORDER P R E S S U R E 7 R * N S O U C I R PRESSURE W A M O D E R A T O R A I R CWSHlWPl lUBE D R A I N % A L V E IREA~OTE 0 3 E R A I E D g ?UMP I O P T I O N A L h

A P P A R A l l t S FOR D E I E R M I N I N i i THE C I I A R A C T E X I S T I C R A l E OF DISCHARGE OF A

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