Rdt Swimming Pool Techl Presentation (PSPE)

7/28/2019 Rdt Swimming Pool Techl Presentation (PSPE)

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BASIC SIZING OF SWMMING POOL

PUMPS , FILTERS AND THREEMETHODS OF FILTRATIONSYSTEM


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Hydraulics is the study and understanding of the

behavior of liquids at rest and in motion.

We are concerned with water, and we have the

following four characteristics of our application:


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1. How much water do we have (Pool Capacity)?

2. How fast do we want to move the water (Turnover Rate)?

3. How much resistance will this water meet while moving

through the system (Friction Loss)?

4. How will we overcome this resistance (Pump/Filter Sizing)?


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Following are step by step instructions to answer

these four questions, and ultimately, determine theproper size pump or filter for virtually any aftermarket

installation.

Each step is a calculation based on the following

example: 5.00 m by 10.00 m rectangular pool,0.90m. to 1.50m deep .

With an existing 1 H.P. pump; filter gauge reads 10

P.S.I. (clean).


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1. Pool Capacity

To determine total gallons, we must first calculate thesurface area of the pool in square meter:

A.Surface Area

Area = (A+B)x L x .45 Area = R x R x 3.1416 Area = L x W

_____________m 2

(surface area )

Surface Area: 5.00m. X 10.00m. = 50.00 m 2

Next, multiply the square met er by average depth to determine the approximate cube of the pool:


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B. Average Depth

( __________m + _________ m ) 2 = __________m(depth shallow end) (depth - deep end) (average depth)

Average Depth : (0.90m + 1.50m.) 2 = 1.20 m.

C. Cube

___________m2 + __________ m = _________ m3(surface area) (average depth) (cube)

Cube : 50.00m.2 x 1.20m. = 60.00m3

D. Pool Capacity

________m x 264.171 gallons /m3 = ________ gallons

Pool Capacity: 60.00m3 x 264.171gals = 15,850 gallons


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Once the pools capacity has been calculated, the next step is to determine how

fast the water must be circulated in Gallons Per Minute (GPM), to meetreasonably clean, safe water standards. The recommended minimum

standards for swimming pools are not less than the flow rate to provide one (1)

full turnover of the pool every twelve (12) hours . However, an eight (8) to ten

(10) hour rate is quite common:

A.Turnover Rate in Gallons Per Hour (GPH)____________ gallons _________________ hours = ____________GPH

(pool capacity) (desired turnover time) (turnover rate

gallons per hour)

Turnover rate : 15,850 gallons 10 hours = 1,585 gallons per hour

B.Turnover Rate in Gallons Per Minutes (GPM)______________ gallons/ hour 60 minutes = ______________ GPM

(turnover rate - (turnover rate -

gallons per hour) gallons per minute)

Turnover rate : 1,585 gallons per hour 60 = 26 GPM


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A. Friction Loss (Vacuum)

______________ in. mercury x 1.13 ft. of water = ____________ ft. of water(vacuum reading) (total resistance vacuum)

Or COMMON HEAD LOSS FACTORS

Vacuum (At Pump) Assumes 2 suction line, not to exceed 40 long, minimal

fittings, one (1) 2 valve and full rated pumps.

H.P. Pump 4.5 to 5.5 ft. of water 1 H.P. Pump 10 to 12.5 ft. of water

1 H.P. Pump 7 to 9 ft. of water 2 H.P. Pump 13.5 to 16 ft. of waterTotal Resistance (Vacuum): 9 ft. of water (existing 1 H.P. pump)

B. Friction Loss ( Pressure)

_______________ P.S.I. X 2.31 ft. of head/ P.S.I. = ____________ft. of head( filter- clean) (total resistance pressure)

Total Resistance (Pressure): 10 P.S.I. x 2.31 = 23 ft. of head


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C. Total Dynamic Head____________ ft. of water + __________ft. of head = ________ft.of head(total resistance vacuum) (total resistance- pressure) (totalresistance to flow)

Total Resistance to flow : 9 ft. of water + 23 ft. of head = 32ft. of head

NOTE: the table below provides a maximum flow (GPM)through 1 and 2 PVC pipe without exceeding themaximum standards for velocity (ft./ sec.), i.e., suction line(8ft./ sec.) and return line (10 ft./ sec).Pipe Size (PVC) Suction Line Return Line

1 50 GPM 65 GPM

2 85 GPM 105 GPM

2 125 GPM 150 GPM


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Re Cap

We now have all of the information necessary to select the

proper size pump and / or filter. To re cap, enter the finalcalculations from the previous three sections in the spaces

below, which will see as our road map to sizing:

Pool Capacity ___________ gallons

Turnover Rate ___________ gallons per minute (GPM)

Friction Loss ____________ ft. of head

Pool capacity: 15,850 gallons

Turnover rate: 26 GPM

Friction loss: 32 ft. of head


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4. A . Pump SizingSince the one and only function of the pump is to overcome the

total resistance to the flow of the system, proper selection is ofutmost importance. A pumps performance data is to provide inGPM (output) vs. Feet of Head (resistance). See the table below forthe specific performance data for a Hayward pumps.

Performance Data Pump

ModelNo.MaxRated

ModelNo.FullRated

Pump Output (GPM) vs.Total Resistance to Flow

(Feet of Head )

20 ft. 30ft. 40ft. 50ft. 60ft. 70ft.

SP2600X5 - 55 45 29 - - -

SP2605X7

- 67 58 47 31 - -

SP2607X SP2607 85 76 65 50 27 -


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4. B. Filtering SizingA filter, be it D.E, sand or cartridge, has a Design Flow Rate

(in Gallons Per Minute GPM), as well as Turnover Rate ( PoolCapacity in Gallons). See the table below for the specificperformance data for a Hayward filters .

ModelNumber

Effective

Filtration

Area

DesignFlowRate

Turnover(in Gallons)

8 Hours 10 Hours

S180T 1.75 ft. 2 35 GPM 16, 800 21,000

S210T 2.20 ft.

2

44 GPM 21,120 26,400S220T 2.64 ft.2 52 GPM 24,960 31,200

S244T 3.14 ft.2 62 GPM 29,760 37,200

S310T 4.91 ft.2 98 GPM 47,040 58,800

Select S180T (minimum) to adequately filter pool(i.e. 26 VS. 35GPM turnover rate; will handle pools up to 21, 000 gallons in 10hours).

One additional factor to consider in filter sizing is the bathers load.

Busier pools require larger filters. Also, larger filters provide longercycles, reducing the everyday maintenance required by the


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SummaryUsing the information in the re-cap section

above, based upon your calculations, choosethe desired pump and / or filter model , thenselect the proper size component to meet theneeds of the installation.

It is important to remember that yourTurnover Rate calculation is keyed directly toa specific Total Dynamic Head calculation(i,e ,GPM vs. Feet of Head).If you increase or

decrease your GPM for any reason,yourresistance will increase or decrease


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The important of proper swimming pool or spa filtration

cannot be overstated. The reasons for filtration,to removeinsoluble matter such as dirt and algae, and to helpproduce clear,sparkling water are obvious. Clear water notonly looks beautiful, but it is also necessary for health andsafety reasons. Much of the material suspended in thewater, derived from the plants and animal sources whichprovides food for bacteria and algae. It is these materialsthat must be removed if a pool or spa is to be maintainedin a safe and sanitary condition.

The three most popular types of filtration currently in use

in residential pools and spas are HighRate Sand,Cartridge and Diatomaceous Earth (D.E.). Each method offiltration is explained below.


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The oldest and most popular method of filtration is sand.Sand filters share two things in common: 1. When in thefiltration mode , water always flows from top to bottom;2. They all have some sort of lateral or underdrain withslots to hold back sand while allowing clean, filtered water

to pass through.

High rate sand filters use a special filter sand, normally .45 to .55mm (also known as pool grade #20 silica sand),because it has sharp edges that serve to separateparticles, allowing filtration to take place. They operate onthe basis of depth filtration; dirt is driven through thesand bed and trapped in the minute spaces between theparticles of sand. Initially , a clean sand bed will removelarger particles, and then, as the bed starts to load up, itwill remove finer particles.


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Cartridge filtration has been available for a relativelylong time, but only recently has begun to enjoy rapidgrowth and acceptance.

When water passes through a cartridge filter, dirt isscreened out at the surface of the cartridge element.When clean, the element will trap larger particles,with finer particles being filtered out as the pores ofthe element become clogged by the larger debris.

The cartridge element can be removed and cleanedby pressure washing inside and out using a gardenhose.


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Many pool professionals consider D.E filtration tobe the finest, because it is capable of removingsmaller particles than either sand or cartridge.

Diatomaceous earth is a porous powder with

microscopic openings,that,when magnified,lookslike a tiny sponges.Clear water can pass throughthese openings,but particles,as small as one tothree microns,are trapped the first pass throughthe media.

All D.E. filters have internal elements that becomecoated with D.E powder. It is this filter cake thatstrains dirt, dust, algae and some forms ofbacteria from the water.

Similar to sand filters, when a D.E. filter becomes

dirty, it is cleaned either by backwashing the


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Whatever method of filtration is selected,it is important to remember that filtration

alone does not keep water looking itsbest. Proper water chemistry must alsobe maintained for safe,clean water.Mostpool owner complaints are directly relatedto water chemistry or improper sizing offilters and pumps rather than equipmentfailures.


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1. CHLORINE :Chlorine is used as disinfectant orwater purifier. Chlorine level must bemaintained at reasonable limits (0.6

1.0 readings) to ensure that there issufficient amount to adequatelydisinfect the water, but not inexcessive amounts which will irritate

bathers. Apply chlorine preferably inthe evening by hand broadcasting itdirect into the water.


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2. Ph Muriatic Acid:Too much acid (low pH) causes irritation tothe eyes and mucous membrane, algaeprosper and the pool gives off an

unpleasant chlorine odor. The pH readingsmust be between 7.2 7.6 for comfortableswimming. Apply acid one pint at a time bydirectly pouring it around the pool.


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In short, regular chlorine dosages to maintain chlorinereadings at 0.6 1.0 and pH at 7.2 7.6 is all that isrequired to prevent the spread of algae and thus keepthe pool sanitary and attractive.


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Maintenance is a matter of good housekeeping.Vacuum, clean the pool floor and brush sidesthoroughly every morning. Apply chemicals inthe evening and run the filter at least 4 to 6

hours daily. Thats all there is to it.

WHAT TO DO:


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PoolGallonage

Amount ofChlorine

Amount ofAcid (pH)

15,000.00 3 4 oz. daily 3 pints or 1 qts.

20,000.00 4 6 oz. daily 5 pints or 2 qts.

25,000.00 5 7 oz. daily 6 pints or 3qts.

30,000.00 6 8 oz. daily 7 8 pints or 4qts.

35,000.00 7 9 oz. daily 8 9 pints or 4 qts.

40,000.00 8 10 oz. daily 9 10 pints or 5qts.

8 pints = 4 quartz = 1 gallon

Remember, that the above table is only a guide. Your water

test kit will tell you when to put chlorine or acid to the

pool. So always use the test-kit before adding the

chemicals.


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Rdt Swimming Pool Techl Presentation (PSPE)