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How to Calculate Fire Pump and Jockey Pump Capacity in Fire Fighting System?

1.Fire Pump (Electrical Driven / Diesel Driven)

Use Elite fire program

In general :

Total pump head = height from lowest point to the highest point + friction due to pipes and

Fitting to the last point + working pressure of the sprinkler

Calculating pump gpm

To calculate pump gpm, two sizing methods are available, the standpipe method and the sprinkler area calculation. In a fully sprinklered structure with standpipes, NFPA 14 (2010): Standard for the Installation of Standpipes and Hose Systems says that the first standpipe requires 500 gpm and each additional standpipe requires 250 gpm, up to a maximum of 1,000 gpm.

For example, a building with two standpipes would require a 750-gpm pump (500 gpm for the first standpipe and 250 for the second), and a building with five standpipes would require a 1,000-gpm pump because that is the maximum allowed by NFPA 14. (Note that the local code or the insurance carrier may require more than the maximum allowed by NFPA 14.)

Area calculations are more difficult. You need to know the sprinkler hazard classifications of the building and its contents to determine the design density, and the square footage (area of operation) of each hazard must be calculated. The five types of hazard classifications from NFPA 13 (2010): Standard for the Installation of Sprinkler Systems are:

• Light hazard: Low quantity of combustibles with low heat release (e.g., churches, hospitals, museums)
• Ordinary hazard 1: Moderate quantity of combustibles with moderate heat release and eight-foot stockpiles (e.g., mechanical rooms, restaurant kitchens, laundry facilities)
• Ordinary hazard 2: Moderate quantity of combustibles with moderate heat release and 12-foot stockpiles (e.g., stages, large library stack rooms, repair garages)
• Extra hazard 1: High quantity of combustibles with high heat release and no flammable or combustible liquids (e.g., aircraft hangers, saw mills)
• Extra hazard 2: High quantity of combustibles with high heat release and flammable and combustible liquids (e.g., plastics processing, flammable liquids spraying)

Refer to NFPA 13 for a more thorough definition of the classifications.

Once the hazards have been determined, you next take the most remote 1,500-square-foot area of sprinkler operation and multiply it by the density found in NFPA 13 . Then you must add the inside and outside hose stream demand to the area calculation. This information can be found in NFPA 13 Table . Hose stream demand is the amount of water that must be added to the sprinkler system hydraulic calculation to fill the hoses as well as ensure enough supply to operate the sprinklers. Inside hoses are generally 1- to 1½-inch standpipe hoses that may be connected to the sprinkler system for initial fire attack.

For example, if you have a 40,000-square-foot building that is all ordinary group 1, the calculation would be 1,500 x 0.15 (density) = 225 + 250 (hose demand) = 475 gpm total for the fire pump.

If the structure has multiple hazards, the hazard with the highest gpm calculation dictates the pump size. Make sure you touch base with the insurance carrier for a particular project, as they may require higher square footage or density requirements, depending on the job.

How to Calculate  Jockey Pump Capacity in Fire Fighting System?

2.Jockey Pump

A jockey pump is an important component of fire fighting system. Jockey pump or pressure maintenance pump is a small apparatus that works in conjuction with a fire pump as part of a fire-protection sprinkler system. It is designed to keep the pressure elevated so that the main fire pump is prevented from running unless absolutely necessary. From time to time, unwanted pressure drop, small water leaks, or even temperature changes may “fool” the fire pump into starting when it is not necessary.

A jockey pump is electric motor driven. It is controlled with a pressure switch in the main trunk. It will switch the pump on and off periodically to maintain trunk main pressure at high level.

How to Size Capacity of a Jockey Pump

I have browsed the answer to this question and I found several answer. My colleague who asked me the question also has his own answer. He thought the capacity of a jockey pump should be about 5-10% of main fire pump. I also found the exactly similar answer. In this source, jockey pump with the capacity of 5-10 gpm is usually acceptable. And at different source, for example in this source, the jockey pump capacity is 1% of main pump capacity. So, which one is true?

I think it will be better to refer NFPA (National Fire Protection Association). Based on NFPA 20 year of 1999 Standard for the Installation of Stationary Pumps for Fire Protection , pressure maintenance pumps (jockey pumps) shall have rated capacities not less than any normal leakage rate. The pump shall have discharge pressure sufficient to maintain the desired fire protection system pressure. So, the first thing to do to size the capacity of a jockey pump is to look at the system and to calculate normal leakage rate.

Based on NFPA 24 year of 1995 Standard for the installation of private fire service mains and their appurtenances, maximum leakage per 100 joints is 2 quatz per hour or 0.5 gallon per hour. The standard requires the water and the pressure to be replenished within ten minutes. We also need to take into account:

Net positive suction pressure available

Effect of rise to shutoff the system to prevent over pressure

  

Hi Viewers I am Afreen Ali . i bring this video for basic chilled water pump  head for primary pump / head for secondary pump. Kindly Subscribe my channel AfreenAli

Head for primary pump / head for secondary pump

Head for primary pump = chiller friction losses + pipe losses for longest pass + fitting losses

Head for secondary pump = pipe losses for longest pass + fitting losses + last equipment in the longest pass ( FCU or AHU )

there is tow way to calculate the pump head

1- equivalent length method and you may found it in carrier handbook.

2- k factor you will find it in ASHRAE.

the main concept for calculation and sizing

pipe size < = 2" -----> Max velocity = 4 fps

pipe size > 2" --------> max friction losses 4ft wg / 100 ft

there are many programs for pump head calculation like

H-sym (Elite) , Trane pipes , pipe flow expert

Example mention below with details

There is a difference between the pressure required from pump which is generated by the pump itself (dP)and the hydrostatic pressure generated by elevation

the fist one, we considered it for moving the fluid but the second one we considered it for determining the max. working pressure inflicted upon pipes, pump's parts (casing , mechanical seal ,....)and all the elements in network

example:

If we calculate dP=5bar required from pump to move the water with the required flow rate.

these 5bar may be from 1bar to 6bar

and may be from 15bar to 20bar

The 2 cases have the same dP (friction losses and fittings ,....) but not the same max. working pressure

Such as (Example), the maximum pressure the chiller would see, if on the bottom floor, is approximately 900 ft (due to elevation) + 140 ft (due to pump shut off pressure, which is basically the TDH provided by the pump during operation and the shut off pressure of the pump) for a total static pressure of 1040 ft (450 psi) per Solution A. This would exceed the rated pressure of the described fitting/chiller.

If the chiller is on the top floor (Solution C), then the total pressure the chiller would see would be 65 psi. This would be within the pressure rating of the fitting/chiller. The pump is still contributing 140 ft to the pressure, but because of the difference in elevation, the static effect is much less.

In this case you would specify fittings/pipe with higher pressure ratings on the lower floors and decreasing ratings as you went up. You would locate the chiller at a level where the pressure does not exceed its maximum pressure.

I hope that helps.

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IMPORTANT INTERVIEW QUESTIONS Plumbing Engineering

Plumbing:-

1)      Pump head:

Total Head = Total Suction head – total discharge head

Total suction head = total ht from the centre line of pump to max ht of pipe run + Total friction head + total surface pressure head (is 0 wn tank is open)

Total discharge head = total ht from the centre line of pump to max ht after discharge + Total friction head + total surface pressure head.

2)      Pressure head is a term used in fluid mechanics to represent the internal energy of a fluid due to the pressure exerted on its container. It may also be called static pressure head or simply static head (but not static head pressure). It is mathematically expressed as:

  

where

 is pressure head (Length, typically in units of m);

 is fluid pressure (force per unit area, often as Pa units); and

 is the specific weight (force per unit volume, typically N/m³ units)

 is the density of the fluid (mass per unit volume, typically kg/m³)

 is acceleration due to gravity (rate of change of velocity, given in m/s²)

Note that in this equation, the pressure term is gauge pressure, not absolute pressure.

 

Where Fr = Friction loss = 0.1

L= length

Pr = Pressure head

3)      Total Static pressure:

TSP = Static pressure + (Density x (Vel)²)

                                                                2

*Duct Static Pressure = Total Friction loss (L/D*0.0195*VP) + Dynamic  loss (Dinamic loss cofficient*VP) {note l & d are in feet & VP = (velocity/4005)^2}

4)      1 psi = 6894.7 Pa = 0.0689 bar ; 1 bar = 100,000 Pa =29 inhg = 401 inh2o .

5)      How to find pipe dia = GPM * Velocity (FPM) {you will get friction and pipe size from the graph}

6)      Isolating valve = Ball valve = gate valve = Butterfly valve.

7)      Check valve = non return valve

8)      Pressure reducing valve - Whenever pressure increases the limit, it will regulate pressure and it is connected to BMS system.

9)      Double check valve = Back flow preventer

10)   What are the fittings of faucet drainage etc., - Mixer, valves, flexible connecting pipes, etc..

11)   How to determine stack sizes and how many types are there. – Vent stack, Waste stack, Soil stack. Varies with load on each floor.

12)   What are the normal codes followed for drainage and plumbing in ksa.

1)      NPC = National plumbing Code.

13)   What are the software used for calculating the pipe sizes and hot water cal etc.,:- epipesizer, elite pipe, pocketpipe, s-pipe, PP calculator, Etc.

14)   What is use of U-Trap and where it is used? It is used in Drain connection as water seals/smell.

15)   What should be the max distance between sewer line & portable water line? 3 meter.

16)   How much size of clean out is provided for sewer pipe below 10" dia? 6"

17)   What are the different pipe material used in plumbing installation?

CI,Acid resistant CI,Bituminous fiber pipe,virtified clay pipe,Lead pipe,Galvanized steel pipe, Galvanized wrought iron pipe,brass pipe,copper pipe,Plastic & synthetic pipe, UPVC, CPVC.

18)   What are the impotant factor to consider while installing waste pipe?

Selection of right kind of material,

Conservative use of fittings.

Right location of cleanouts.

Right pitch or slop of pipe line.

Manner of joining the pipe.

19)   What should be the distance between manholes? 15 m.

20)   What are the different materials used for underground water supply? uPVC (Cold water), cPVC (Hot water), ..

21)   How to find friction in pipes? There is a graph on which if you know two values you can find the others … the graph copy is attached.

22)   Stiffness of GRP Pipes: 2500 N/m2 (this class of pipe can be used for the earth load(truck load+ earth load) depth that is 2 m to 4m which will not exceed the long term deflection of 5%), 5000, ( this class of pipe can be used for the pipes in trench depth (or depth of cover) of 7m), and

10000 N/m2 ( this class is used for the pipes with depth of cover of more than 7m like for 10 m).

23)   1N/m2 = 1Pa.

24)   Pipe Spool: - The term "pipe spool" or "spool piece" refers to a prefabricated section of a piping system that includes the pipe, fittings and flanges that are pre-assembled in the fabrication facility and then transported to the field. The reason for pre-assembly is that hoists, gauges, material and tools are available for the assembly in a controlled environment. The size of the spool pieces is limited by factors related to transportation to the site and ability to handle the spool piece at the site during assembly.

25)   Efficiency of Pump = GPMxTotal Headx100/Input HPx3960.

26)   Tank to Pump – Service connection details (shown in the ‘Plumbing Notes file’).

27)   Class of water supply pipes upvc pvc cpvc pipes? – (Shown in ‘Plumbing Notes file’)

Google Drive MEP(HVAC , Plumbing, Fire Fighting and Electrical) complete Design Data and Drawings

Link is below ....

https://za.gl/LS2YOE

Fire Fighting :-ENGINEERS /QA/QC/SUPERVISORS/ INSPECTORS PROFESSIONAL INTERVIEW

1)      What are the types of pump sets used and why in fire fighting?

Jockey pump – used when there is a pressure drop of 1 bar.

Diesel pump – used in case of power shut down.

Electric pump – Main pump starts instantly in case of fire and will cutoff @ 7 bar.

2)      What is fire alarm check valve?

It allows flow in one direction and prevents backward flow and with this gives signal to BMS with alarms.

3)      What is FM-200 and where is it used?

Heptafloropropane is colorless, liquefied compressed gas. It is stored as a liquid and dispensed into the hazard as a colorless, eclectically non-conductive vapour that is clear and does not obscure vision.

It is used in communication rooms, electrical rooms, computer rooms etc..

4)      Types of detectors? Smoke & Heat detectors.

5)      Do we use strainers in fire pumps? Why?

No, we don’t use it because the water coming is portable usually only in cases where we are using river or lake water then we require strainers. Else we prefer not to use them as it will reduce suction flow.

6)      Radius of a sprinkler? it is 1.5 m

7)      What is the distance between each sprinkler? Its 3 m to 4m.

8)      Working pressure of fire system? Its 10 bar.

9)      What is Siamese Connection?

Used as auxiliary connection through which the fire department can pump water to supplement existing water supplies.

10)   What are the Settings of Diesel pump upon how much pressure it is cut off? Don’t know ck internet.

11)   What is OS&Y, Tamper switch, Pressure switch and their working?

OS&Y valve - Outside screw & Yoke – is used in fire system mains and is used for easy knowing whether it is in open position or  closed as we cannot know from a typical gate valve or ball valve.

Tamper switch - It is a supervisory device located on the control valves of a fire protection system. The tamper switch is a device which, when connected to an alarm panel or sounder, signals a disturbance (opening or closing) at the control valves of the system.

Pressure Switch - These critical components sense the activation of the system and then electrically secure the ventilation systems operating in the protected space.

12)   What is the use of strainer? It is installed before the cooling coil to protect dirt & foreign material entering into the cooling coil /evaporator.

13)   What is the use of staircase pressurization?

To provide fresh & clean air in the staircase when fire occurs in the floor. The pressurized air keeps the smoke away from the stair wall. It is used for creating positive pressure.

14)   Name some fine controlled Valves? Needle valve,Spindle valve, regulating valve, motorized valved etc.

15)   What should be height of fire cabinet from floor level? 1 m.

16)   What are the different types of sprinkler heads used in fire protection system?

Upright sprinkler, Pendent sprinkler, Side wall sprinkler, Pendent Recessed sprinkler, extended side wall sprinkler, extended coverage etc.,

17)   What is the test pressure for firefighting pipe network? 1.5 times working pressure.

18)   What is the temperature rating for firefighting sprinkler head? 170°F or 76°c.

19)   What is the fire department connection known as? Siamese.

20)   Name the different types of fire extinguisher? Portable type CO2, Portable type Dry Powder & water.

21)   What are the different types of Valve used in fire protection system? Alarm valve, Zonal valve etc.

22)   What the pipe material used for underground fire piping? UPVC, MDPA, RTR.

23)   What is zone control valve?

It is used in ff system on every floor … it consist of OS & Y Gate valve with tamper switch, Check Valve, pressure gauge, Drain point, Flow meter & Sight glass. “Check FF Notes”.

24)   What is the standard length of hose in a hose reel cabinet? 30m.

25)   Pipe material used in FF system and which class? ‘Check FF Notes’.

26)   Floor Control Valve Assembly? ‘Check FF Notes’.

27)   Name the pipe materials used in Water supply? ‘Check FF Notes’.

End of Question & Answer.

Best of Luck

J

Fire Fighting Pumps Details

Fire Fighting Pumps Details:
A fire pump is a part of a fire sprinkler system's water supply and powered by electric, diesel or steam. The pump intake is either connected to the public underground water supply piping, or a static water source (e.g., tank, reservoir, lake). The pump provides water flow at a higher pressure to the sprinkler system risers and hose standpipes. A fire pump is tested and listed for its use specifically for fire service by a third-party testing and listing agency, such as UL or FM Global. The main code that governs fire pump installations in North America is the National Fire Protection Association's NFPA 20 Standard for the Installation of Stationary Fire Pumps for Fire Protection.
either by an electric motor or a diesel engine, or, occasionally a steam turbine. If the local building code requires power independent of the local electric power grid, a pump using an electric motor may utilize, when connected via a listed transfer switch, the installation of an emergency generator.
The fire pump starts when the pressure in the fire sprinkler system drops below a threshold. The sprinkler system pressure drops significantly when one or more fire sprinklers are exposed to heat above their design temperature, and opens, releasing water. Alternately, other fire hoses reels or other firefighting connections are opened, causing a pressure drop in the fire fighting main.
Fire pumps are needed when the local municipal water system cannot provide sufficient pressure to meet the hydraulic design requirements of the fire sprinkler system. This usually occurs if the building is very tall, such as in high-rise buildings, or in systems that require a relatively high terminal pressure at the fire sprinkler in order to provide a large volume of water, such as in storage warehouses. Fire pumps are also needed if fire protection water supply is provided from a ground level water storage tank.
Types of pumps used for fire service include: horizontal split case, vertical split case, vertical inline, vertical turbine, and end suction.

Heavy Duty Exhaust Fan Installation

exhaust fan - a fan that moves air out of an enclosure. attic fan - a fan that blows heated air out of the attic of a building. fan - a device for creating a current of air by movement of a surface or surfaces.

Inline Exhaust Fan Details

Duct Mounted In-Line Fans. ... Commercial and industrial supply or exhaust air applications such as shopping centres, office buildings and car parks, through to industrial processes and equipment ventilation.

An inline exhaust fan is best defined as a fan that is mounted inline (inside or connected to ducting) that is used for extraction purposes.