Resultados y comparativa con otras heurísticas

Capítulo 3 Comprobación del simulador. Heurística “DH”

3.3 Resultados y comparativa con otras heurísticas

1 Installation:

• Mounting plinths comply with instructions for size, construction and location

• The baseplate has been accurately levelled and adequately supported.

This prevents distortion and makes achievable the final shaft alignment to within manufacturers specification

• The fixing bolts are grouted as instructed and tightened to the required torque

• The shaft alignment has been checked and set to within the stated tolerances.

2 Suction and delivery pipework is adequately supported and NEGLIGIBLE forces are transmitted to the pump casing.

3 Where applicable, all drain, minimum flow, and test pipelines are fitted, together with valves gauges and flow meters.

4 The diesel engine exhaust has been fitted in line with recommendations.

5 The engine fuel tank is filled with sufficient fuel.

6 Batteries are filled and charged in accordance with the manufacturer’s instructions.

7 All wiring to controls and to remote alarm panels is completed in line with appropriate regulations & power supplies are connected.

8 The area is clear of all builders’ material and rubbish to allow access to the pumps.

Contents

3 4

hyDRaUlIC DEsIgn Data

Contents

3 4

sECtIon 10

PREssURE (

bar

) Vs hEaD (

m

^{oF WatER)}

bar00.10.20.30.40.50.60.70.80.9 0.000.001.022.043.064.085.106.127.148.169.18 1.0010.1911.2212.2413.2614.2815.3016.3217.3318.3519.37 2.0020.3921.4122.4323.4524.4725.4926.5127.5328.5529.57 3.0030.5931.6132.6333.6534.6735.6936.7137.7338.7539.77 4.0040.7941.8142.8343.8544.8745.8946.9147.9348.9549.97 5.0050.9952.0053.0254.0455.0656.0857.1058.1259.1460.16 6.0061.1862.2063.2264.2465.2666.2867.3068.3269.3470.36 7.0071.3872.4073.4274.4475.4676.4877.5078.5279.5480.56 8.0081.5882.6083.6284.6485.6586.6787.6988.7189.7390.75 9.0091.7792.9793.8194.8395.8596.8797.8998.9199.93100.95 102030405060708090100bar 101.97203.94305.91407.88509.85611.82713.79815.76917.731019.70metres

Contents

3 4

ExaMPlE

Find the metres head of water (1.0 s.g.) equivalent of 54.76 bar

From bottom two lines: 50.00 bar = 509.85m

Select ‘4 bar’ line in first column and read along to figure under 0.7 in top line, hence:

4.70 bar = 47.93m

For 0.06 bar, read under 0.6 top line:

hence 6.12m dividing both figures by 10:

0.06 bar = 0.612m

thus by addition 54.76 bar = 558.392m note:

For liquids with specific gravities differing from 1.0, answer must be divided by actual specific gravity to obtain head in metres of liquid.

seCtiON 10hyDRaUlIC DEsIgn Data

Contents

3 4

sECtIon 11

CalCUlatIon oF hEaD FoR PUMP sElECtIon

To fulfill a pumping duty a pump must develop sufficient head and meet the suction conditions. The total head of a system must take into account the difference in liquid levels at inlet and outlet, friction in the pipes, surface pressure (or in some cases vacuum) on inlet and outlet and the velocity of the fluid at discharge. The following diagram and example explains how to calculate the system head taking all these factors into account.

• hd = total discharge head

• hsd = discharge static head

• hpd = discharge surface pressure head

• hfd = discharge friction head

• hvd = discharge velocity head

System head = total discharge head - total suction head

H = hd – hs

The total discharge head is made from four separate heads:

hd = hsd + hpd + hfd + hvd

Contents

3 4

The total suction head consists of four separate heads hs = hss + hps - hfs - hvs

• hs = total suction head

• hss = suction static head

• hps = suction surface pressure head

• hfs = suction friction head

• hvs = suction velocity head Example

Calculate the total head of the following pump system.

The total friction through suction pipes and fittings is equivalent to 1m head and through delivery pipes and fittings is equivalent to 10m head.

The header tank and discharge pipe is open to atmosphere at sea level.

The suction velocity head is 0.1m and the discharge velocity head is 0.5m

Pumped fluid is cold clean water.

seCtiON 11hyDRaUlIC DEsIgn Data

Contents

3 4

First we calculate the total delivery head, hsd and hss – from the diagram we can see that the discharge static head is 40m and the suction static head is 5m hpd –

millimeters of mercury x = meters of liquid

pressure at sea level is approx. 760mm Hg, specific gravity of cold clean water is 1, so 760 x 0.014/1 = 10.6m

so hpd is 10.6m, the header tank is also open to atmosphere so hps is also 10.6m

hd = hsd + hpd + hfd + hvd

= 40 + 10.6 + 10 + 0.5

= 61.1 m

hs = hss + hps - hfs - hvs

= 5 + 10.6 - 1 - 0.1

= 14.5 m

Total system head H = hd – hs

= 61.1 – 14.5

= 46.6 m

note:

Gauge readings need correcting for height of gauge mounting. For this purpose it is important that pressure gauges should be full of liquid. Where a vacuum gauge is used for a suction lift, the gauge pipe should be left empty and correction made from the point of connection, not from the gauge itself.

0.014 specific gravity

Contents

3 4

aUtoPRIME PUMPIng tERMs head

“Total Head from all Causes” is the combination of both “Total Suction Head and “Total Discharge Head”.

When static heights are kept to a minimum and pipework of the correct size for the pump is used, performance will be maintained and running costs minimised.

Suction head will be affected by changes in liquid viscosity and specific gravity and in the vapour pressure resulting from increased liquid temperature.

net Positive suction head (nPsh)

NPSHr: minimum liquid head (pressure) required by the pump at the impeller to pump the liquid, this is determined by the pump design. NPSHa: minimum liquid head (pressure) available from the atmosphere to deliver the liquid to the impeller for pumping.

Example:

NPSHa (Available) 10.5 m

less Static Lift 3.0 m

Friction & Vapour Loss 1.5 m

NPSHr (Required) 2.0 m

therefore leaving for suction lift 4.0 m

seCtiON 11hyDRaUlIC DEsIgn Data

Contents

3 4

tyPICal sUCtIon lIFt ConFIgURatIon

AUTOPRIME

TOTAL HEAD FROM ALL CAUSES Total

Discharge Head Discharge

Hose Friction

Static Delivery

Head

Static Suction

Lift

Suction Hose Friction

Contents

3 4

sECtIon 12

FRICtIon loss FoR WatER (m/100m) In sMooth anD nEW UnCoatED stEEl PIPEs (haZEn-WIllIaMs FoRMUla, C=140) NB Figures assume actual bores exactly equal to nominal bores. See following notes regarding corrections for actual bores of commercial pipes differing from nominal bores.

45 1.76 0.92 0.52 250(10) 3.7

50 2.1 1.11 0.63 0.38 4.5

Nominal and actual bores of pipes in mm width with nominal inch equivalents.

seCtiON 12hyDRaUlIC DEsIgn Data

Contents

3 4

For other types of pipe, multiply foregoing figures as below, for pipes in smooth and new condition.

Galvanised iron 1.33

Uncoated cast iron 1.23

Coated cast iron, wrought iron, coated steel 1.07

Coated spun iron 1.04

Smooth pipe (lead, brass, copper, stainless steel, glass, plastic) 0.88

Friction losses are affected to an even greater degree by deviations of actual bore from the standard dimensions represented in the foregoing table.

To correct for actual bore, multiply also by

(D/d)^4.87

Where D = Standard (nominal) bore.

d = Actual internal diameter.

Multiplying factors for grey iron pipes to BS 4622 (both sand mould cast and spun): ductile iron pipes to BS 4772: and uPVC pipes to BS 3505 taking into account the corrections both for type of pipe and for actual bore, are as follows on the next page.

Contents

3 4

53 nominal bore mm20253240506580100125150175200225250300 (in)(¾)(1)(1¼)(1½)(2)(2½)(3)(4)(5)(6)(7)(8)(9)(10)(12) grey Iron, bs 4622: Class 1 (spun)---0.840.90-0.93-0.95-0.960.97 Class 2 (spun)---0.910.97-0.99-1.00-1.001.00 Class 3 (spun)---0.991.04-1.04-1.04-1.041.04 Class 4 (spun)---1.181.21-1.16-1.14-1.131.12 For sand mould cast pipes multiply by 1.03: also for uncoated bore pipes by 1.15 Ductile Iron, bs 4722: Class K9---0.730.97-0.77-0.78-0.800.78 Class K12---0.820.88-0.85-0.86-0.870.84 uPVC, bs 3505: Class b---0.780.650.680.680.730.740.770.750.80 Class C-0.570.680.830.720.790.790.840.850.880.860.90 Class D0.660.640.780.960.840.920.920.980.971.030.981.04 Class E0.750.750.911.120.971.061.071.131.101.161.121.19 steel tubes, bs 1387 medium; also x 1.24 for galvanised

0.790.750.640.900.840.851.060.870.920.93----- seCtiON 12hyDRaUlIC DEsIgn Data

Contents

3 4

sECtIon 13

REsIstanCE In FIttIngs

As in straight pipe, having length of following multiples of pipe diameter:

Flush sharp-edged entry 22

Slightly rounded entry 11

Flush bellmouth entry 4

Sharp entry projecting into liquid 36

Bellmouth entry projecting into liquid 9

Footvalve with strainer 113

Round elbow 45

Short radius bend 34

Medium radius bend 18

Close return bend 100

Tee: straight through 11

side outlet, sharp angled 54

side outlet, radiused (swept tee) 22

Branch piece, straight through 7

Branch piece, flow to branch 45

Branch piece, flow from branch 22

Sluice (gate) valve 7

Reflux (back pressure, non-return) valve 45

Angle valve 225

Globe valve 450

Bellmouth outlet 9

Sudden enlargement 45

Taper, divergence angle above 60º 45

Taper, divergence angle 15º - 60º 22

Taper increaser or reduced with less than 15º divergence angle: Equivalent to pipe of mean diameter.

Flap 0.06m Head

note:

Multiplying factor for type and class of pipe to be applied to above equivalent lengths for pipe fittings (elbows, bends, tees etc) but not to those for valves.

Contents

3 4

sECtIon 14

QUantItIEs PassED by PIPEs at DIFFEREnt VEloCItIEs

sECtIon 15

RECoMMEnDED MaxIMUM FloW thRoUgh ValVEs (l/s)

actual bore of pipe, mm Velocity

of flow, m/s

50 80 100 125 150 175 200 225 250 300

l/s

1 1.96 5.03 7.85 12.27 17.67 24.1 31.4 39.7 49.1 70.7 1.5 2.95 7.54 11.78 18.41 26.51 36.1 47.1 59.6 73.6 106.1 2 3.93 10.05 15.71 24.54 35.34 48.1 62.8 79.5 98.2 141.4 2.5 4.91 12.57 19.64 30.68 44.18 60.1 78.5 99.4 122.7 176.7 3 5.89 15.08 23.56 36.82 53.02 72.2 94.3 119.3 147.3 212.1 3.5 6.87 17.59 27.49 42.95 61.85 84.2 110 139.2 171.8 247.4 4 7.85 20.11 31.42 49.09 70.69 96.2 125.7 159.0 196.4 282.8 5 9.82 25.13 39.27 61.36 88.36 120.3 157.1 198.8 245.4 353.4

size of Valve, mm 50 65 80 100 125 150 175 200 250 300 Foot valve with

strainer

2.2 4.0 6.0 12.0 20.0 30.0 40.0 55.0 90.0 130.0

back pressure valve 3.0 5.0 8.0 15.0 25.0 37.5 50.0 70.0 110.0 160.0 sluice valve 5.5 10.0 15.0 25.0 40.0 60.0 80.0 100.0 160.0 220.0

seCtiON 13/14/15hyDRaUlIC DEsIgn Data

Contents

3 4

sECtIon 16

QUantItIEs oF WatER DIsChaRgED by RoUnD sPRay holEs In thIn WallED PIPEs UnDER DIFFEREnt PREssUREs

Pressure (bar)head (m water)

size of hole (mm) 345681012 l/s per hole 0.55.10.0430.0770.1200.1730.3070.480.69 1.010.20.0610.1090.1700.2450.4350.680.98 1.515.30.0750.1330.2080.3000.5320.831.20 2.020.40.0860.1540.2400.3460.6150.961.38 2.525.50.0960.1720.2690.3870.6881.071.55 3.030.60.1060.1880.2940.4240.7541.181.70 3.535.70.1140.2040.3180.4580.8141.271.83 4.040.80.1220.2180.3400.4890.8701.361.96 5.051.00.1360.2430.3800.5460.9721.522.19 6.061.20.1500.2660.4160.6001.0651.672.40

Contents

3 4

sECtIon 17

nEt PosItIVE sUCtIon hEaD (nPsh)

For a pump to fulfil a particular duty it must first be able to get the required quantity in. For example, a pump may work satisfactorily when installed at a given height above the liquid level on the suction side, but no longer do so if it is placed higher, even though the total head remains unaltered in view of a corresponding reduction in the height of lift on the delivery side.

The criteria for this is termed NPSH, which has two aspects, the NPSH the installation and operating conditions provide (NPSH available) and the NPSH needed to get stable flow into the pump impeller (NPSH required). The installation conditions and pump selection must be reconciled so that the NPSH required does not exceed the NPSH available.

Fluid not being sensibly cohesive, it cannot be towed. To be made to flow, it must be pressed from behind. There must, therefore, be either an extraneous pressure on the liquid and/or a head of the liquid itself, which is sufficient to cover losses as far as the pump inlet and then overcome pump inlet losses and create the requisite velocity into the impeller vanes.

The pressure available behind a liquid for creating movement is the absolute pressure on the liquid free surface, less the liquid’s own pressure to move in the opposite direction, i.e. to evaporate into the spaces above the free surface – this is called vapour pressure. The head available at the pump inlet for getting the flow into the pump impeller is

therefore:-• Absolute pressure on liquid free surface Ha

• Plus height of liquid free surface above pump impeller + hs

• Less liquid vapour pressure - hv

• Less losses between liquid free surface and pump inlet - hl (All expressed in metres head of the liquid).

seCtiON 16/17hyDRaUlIC DEsIgn Data

Contents

3 4

note:

+hs becomes negative if the liquid free surface is below the pump impeller.

Care must be taken to state NPSH available taking all these factors into account, even though in particular cases the two may equalise each other, e.g.

with a liquid at boiling point hv equals Ha and they thus cancel each other out.

Otherwise confusion may arise through statement of NPSH, which is plainly inconsistent with the circumstances, e.g. a figure being quoted as NPSH when head over suction hs is meant.

The velocity required at inlet to the impeller vanes is a function of flow quantity, area at vane inlets and velocity induced by impeller rotation.

Consequently the NPSH required varies with pump type and size, and increases with both capacity and speed.

To maintain NPSH required within given limits, the permissible speed reduces approximately as the square root of capacity increases.

The increased vapour pressure of warm water often affects suction as indicated by the following table.

Negative figures represent minimum requirement of head of liquid above impeller eye.

note:

The above figures are intentionally conservative in order to cover varying suction capabilities of different pumps. Better values may be obtainable especially when the normal capacity of the pump is above the output required, but to allow investigation, full details should be submitted, and the possibility of the temperature being underestimated should not be overlooked.

temp of water ^oC 40 50 60 70 75 80 85 90 95 100

suction limit (m) 6.25 5.75 4.75 3.25 2.5 1.5 0.25 -1 -2 -3

Contents

3 4

sECtIon 18

MaxIMUM sUCtIon lIFt WIth baRoMEtRIC PREssURE at DIFFEREnt altItUDEs

sECtIon 19

thERMoMEtER sCalEs Temperature Conversion

Formulae:-oF = (ôC x 9/5) + 32 ôC = (ôF – 32) x 5/9

Comparison values in ^oF and ^oC scales of temperature

altitude (m)

barometric pressure Equivalent head of water (m)

Practical maximum suction

lift of pumps (m)

bar mm hg

Sea level 1.013 760 10,33 6.5

500 0.954 716 9.73 6

1000 0.899 674 9.16 5.5

1500 0.846 634 8.62 5

2000 0.796 597 8.12 4.5

oF ôC ôF ôC ôF ôC

sECtIon 20

lIQUID VIsCosIty anD Its EFFECts on PUMP PERFoRManCE Viscosity is the property of reluctance of a liquid to flow, i.e. the opposite of fluidity.

It involves units of force, length and time and can be expressed as ‘absolute’

in regard to the internal forces in the liquid, or as ‘kinematic’ relating these forces to the liquid specific gravity. The most widely used unit of absolute viscosity is the poise (100 centipoises). However, in all considerations of liquid flow and pump performance the operative factor is the kinematic viscosity, the corresponding unit being the stokes (100 centistokes).

Poises (centipoises) stokes (centistokes) =

specific gravity

Common viscometers (Redwood, Saybold, Engler, etc) give readings having arbitrary relationship to fundamental units. Conversion figures are given in the schedule overleaf. These are approximate only as they may vary slightly with temperature and other factors, and are not universally agreed on, but they are sufficiently accurate for the purposes under consideration.

The only values of interest to the pump engineer are kinematic viscosity at actual pumping temperatures. Viscosities are frequently quoted at standard reference temperatures, commonly 100ºF (37.8ºC) or 60ºC (140ºF). If either of these does not correspond with the actual pumping temperature, the viscosity at the latter must be obtained from product data or estimated from general viscosity/temperature curves.

The performance of a centrifugal pump when handling a viscous liquid depends not only on the viscosity of the liquid but also its relative size and on whether the pump is of low or high specific speed design. The smaller the required pumping duty, the lower the viscosity for which centrifugal pumps are appropriate. For these reasons it is necessary that all enquiries for pumps to handle viscous liquids should be submitted to the pump maker for individual consideration.

In the last column of the schedule, indications have been given of the approximate minimum practical size of centrifugal pump corresponding to each viscosity. In general, for greater viscosities exceeding 25 stokes, pumps of a positive displacement type should be used.

Contents

3 4

CEntRIFUgal PUMP aFFInIty laWs

The affinity laws can be used to show the effect of either speeding up or slowing down the rotational speed of the impeller and also how changing impeller diameter will alter the performance of a pump. The affinity laws state that:

Pump capacity increases in proportion with impeller rotational speed.

∝

Pump head increases in proportion to the square of rotational speed.

∝

^N²

Pump power increases in proportion to the cube of rotational speed.

∝

^N³

Where Q = Capacity, H = Head, P = Power and N= Rotational speed

This allows the change in performance to be predicted as a result of changing the pump speed.

Q₂= Q₁N₂ N₁ H₂ = H₁ N₂ N₁₂ P₂ = P₁ N₂ N₁₃

Where the subscript 1 indicates original condition and the subscript 2 indicates the revised condition.

Increasing either impeller diameter or rotational speed will have the same proportional effect on impeller peripheral speed. This means the same can be applied for changing impeller diameter.

Q₂= Q₁D₂ D₁ H₂ = H₁ D₂ D₁₂ P₂ = P₁ D₂ D₁₃

Where D = Impeller diameter

The affinity laws are proven to work more effectively for some types of pumps as opposed to others and the accuracy of them is dependent on the pump’s hydraulic design. Because of this fact and that there may be other limiting factors (eg. casing or seal pressure rating, bearing life, etc), it is strongly advised the pump manufacturer be consulted before any changes are undertaken.

seCtiON 20hyDRaUlIC DEsIgn Data

Contents

3 4

aPPRoxIMatE VIsCosIty ConVERsIon sChEDUlE

Kinematic Viscosity stokes

Kinematic Viscosity Centistokes

Redwood no 1 seconds

saybolt Universal seconds

Engler seconds

Engler Degrees

Redwood admiralty seconds

saybolt Furol seconds barbey Fluidity

Minimum size Centrifugal Pump (mm) 0.01129.031.051.31.00--6200 No reasonable limitation

0.02230.933.557.51.12--3100 0.03333.036.262.61.22--2067 0.04435.339.167.21.31--1550 0.05537.942.371.31.39--1240 0.06640.545.575.91.48--1033 0.07743.248.780.11.56--886 0.08846.052.084.71.65--775 0.09948.855.489.31.74--689 0.11051.758.693.91.83--620 0.22085.097.51472.87915.031020-25 0.3301231412094.071218.520725-32 0.4401631862745.331622.215332-40 0.5502032313406.612026.012440-50 0.6602442774067.902430.510340-50 0.7702843234739.212835.088.650-65 0.88032437055910.53239.577.550-65 0.99036441660611.83644.068.950-65

Contents

3 4

Kinematic Viscosity stokes

Kinematic Viscosity Centistokes

Redwood no 1 seconds

saybolt Universal seconds

Engler seconds

Engler Degrees

Redwood admiralty seconds

saybolt Furol seconds barbey Fluidity

Minimum size Centrifugal Pump (mm) 110040546267713.24148.562.050-80 2200810924135026.38194.731.080-100 330012151386203039.512214120.7125-150 440016201848270052.616218815.5150-175 550020252310358065.820323512.4175-200 660024302772406078.924328210.3200-250 770028353234473092.12843298.9200-250 88003240369653901053243767.8250-300 99003645415860601183654236.9250-300 1010004050462067701324054706.2300-350 0200081009240135002638109403.10400-450 303000121501386020300395121514102.07 Positive displacement pump required

404000162001848027000526162018801.55 505000202502310033800658202523501.24 606000243002772040600789243028201.03 70700028350323404730092128353290 808000324003696053900105032403760 909000364504158060600118036454230 10010000405004620067700131640504700 seCtiON 20hyDRaUlIC DEsIgn Data

Kinematic Viscosity stokes

Kinematic Viscosity Centistokes

Redwood no 1 seconds

saybolt Universal seconds

Engler seconds

Engler Degrees

Redwood admiralty seconds

saybolt Furol seconds barbey Fluidity

Minimum size Centrifugal Pump (mm) 0.01129.031.051.31.00--6200 No reasonable limitation

Contents

3 4

sECtIon 21

tEst tolERanCEs anD DIFFEREnt stanDaRDs aPI 610 11th Edition

The following tolerances shall apply:

-• Test speed shall be within ± 3.0% of rated speed shown on pump datasheet, at duty point.

• Rated differential head at duty - 0m to 75m ±3%

75m to 300m - ±3%

Over 300m - ±3%

• Rated differential head shutoff - 0m to 75m - ±10%

75m to 300m - ±8%

Over 300m - ±5%

• Rated Power at duty - +4% (Cumulative tolerances are

not acceptable)

• Rated NPSH at duty - +0%

• Efficiency is not a rating value.

note:

= If a rising head flow curve is specified, the negative tolerance specified here shall be allowed only if the test curve still shows a rising characteristic.

british standards – (Class C)

The following tolerances shall apply at duty flow rate:

-• Rate of flow ± 3.5%

• Pump Total head ± 3.5%

• Pump Input power ± 3.5%

• Pump Efficiency ± 5.0%

Contents

3 4

hydraulic Institute test standards

In making tests under this standard no minus tolerance or margin shall be allowed with respect to capacity, total head or efficiency at the rated or specified conditions.

The following tolerances shall apply:

• At rated head +10% of rated capacity OR

• At rated capacity +5% of rated head under 500 feet +3 % of rated head 500 feet and over

Conformity with only one of the above tolerances is required. It should be noted that there might be an increase in horsepower at the rated condition when complying to plus tolerances for head or capacity.

For a fire pump the following tolerances from NFPA 20 shall also apply:

• At 150% of rated capacity, head will range from minimum of 65% to maximum of just below rated head.

• Shutoff head will range from minimum of 101% to maximum of 140% of rated head.

Exception

If available suction supplies do not permit the flowing of 150% of rated capacity, the fire pump shall be operated at maximum allowable discharge to determine if it is acceptable. This reduced capacity shall not constitute an unacceptable test.

seCtiON 21hyDRaUlIC DEsIgn Data

Contents

3 4

Iso 9906:2012 (grade 1) table 10

The following tolerances shall apply at duty flow rate:

-• Rate of flow ± 4.5 %

• Pump Total head ± 3 %

• Pump Efficiency - 3 %

• Speed of rotation ± 1 %

Iso 9906:2012 (grade 2) table 10

The following tolerances shall apply at duty flow rate:

-• Rate of flow ± 8 %

• Pump Total head ± 5.5 %

• Pump Efficiency - 5 %

• Speed of rotation ± 1 %

Iso 9906:2012 (grade 2) annex a.1 – Pumps produced in series.

The following tolerances shall apply at duty flow rate:

-• Rate of flow ± 9 %

• Pump Total head ± 7 %

• Pump Input Power + 9 %

• Driver Input Power + 9 %

• Pump Efficiency - 7 %

Iso 9906:2012 (grade 2) annex a.2 – Pumps with a driver power input less than 10 kW

The following tolerances shall apply at duty flow rate:

-• Rate of flow ± 10 %

• Pump Total head ± 8 %

Contents

3 4

67 67

loss Prevention Council (lPC) The following tolerances shall apply:

-• Rate of flow ± 0 %

• Pump total head +5 %

• Pump input power within duty rating and/or driver rating + 10%

Underwrites laboratories (Ul) The following tolerances shall apply:

-• At rated head +10% of rated capacity OR

• At rated capacity +5% of rated head under 500 feet

• At 150% of rated capacity, the pump will develop not less than 65% of rated head.

• The maximum net pressure for a fire pump shall not exceed 140% of rated head.

note:

No minus tolerance or margin shall be allowed with respect to capacity, total head or efficiency at the rated or specified conditions.

seCtiON 21hyDRaUlIC DEsIgn Data

Contents

3 4

68 3 Contents 4

VEloCIty hEaD

In document Simulador para la resolución de problemas de programación multiproyecto con restricción de recursos. (página 61-73)