Bernoulli's Equation with Example 👍🏻

 

Industrial Cooling Tower Design

 

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Fire Fighting

Fire Protection :

   sprinkler Systems:

         A sprinkler system is an integrated system of underground and overhead piping, designed in accordance with fire protection engineering standards, and connected to one or more automatic water supplies. The system is usually activated by heat from a fire, and the sprinkler heads then discharge water over the fire area. Sprinkler systems are nearly 100 percent effective. Many sprinkler systems are supervised electrically from a central station, and alarms are transmitted to a fire department whenever the sprinklers operate or when a valve in the sprinkler system closes for any reason. If a fire-fighting unit arriving at a fire finds that the sprinkler system is not receiving sufficient water and pressure, a pumper is connected to the sprinkler system to supply additional water.

Standpipe Systems:

         Many high-rise or other large buildings have an internal system of water mains (standpipes) connected to fire-hose stations. Trained occupants or employees of the building management operate the hoses until the fire department arrives. Fire fighters can also connect their hoses to outlets near the fire.

 Fire Extinguisher

I   INTRODUCTION 

          Fire Extinguisher, portable device used to put out fires of limited size. Such fires are grouped into four classes, according to the type of material that is burning. Class A fires include those in which ordinary combustibles such as wood, cloth, and paper are burning. Class B fires are those in which flammable liquids, oils, and grease are burning. Class C fires are those involving live electrical equipment. Class D fires involve combustible metals such as magnesium, potassium, and sodium. Each class of fire requires its own type of fire extinguisher.

Standards for the selection, placement, and testing of portable fire extinguishers are issued by the National Fire Protection Association, a nonprofit technical and educational organization in Quincy, Massachusetts. The standards establish the minimum requirements for all types and sizes of extinguishers that are listed and rated by testing laboratories against standard test fires of the types they are designed to control. Each extinguisher is rated as to both type and size of the fire extinguished. For example, a 20-B extinguisher should extinguish a flammable-liquids fire that is 20 times the size of a fire that an extinguisher rated 1-B would extinguish. Extinguishers that cannot extinguish the minimum size test fires are not listed or rated. Some extinguishers will put out only one class of fire; others are used for two or even three classes; none is suitable for all four classes.

Fire extinguishers may go unused for many years, but they must be maintained in a state of readiness. For this reason, periodic inspection and servicing are required, and that responsibility rests with the owner. Fire department inspectors check at periodic intervals to see that extinguishers are present where required by law and that they have been serviced within the specified time period.

         

II       EXTINGUISHERS FOR CLASS A FIRES

Class A fire extinguishers are usually water based. Water provides a heat-absorbing (cooling) effect on the burning material to extinguish the fire. Stored-pressure extinguishers use air under pressure to expel water. Pump-tank extinguishers are operated by a hand pump.

         

III     EXTINGUISHERS FOR CLASS B FIRES

Class B fires are put out by excluding air, by slowing down the release of flammable vapors, or by interrupting the chain reaction of the combustion. Three types of extinguishing agents—carbon dioxide gas, dry chemical, and foam—are used for fires involving flammable liquids, greases, and oils. Carbon dioxide is a compressed gas agent that prevents combustion by displacing the oxygen in the air surrounding the fire. The two types of dry chemical extinguishers include one that contains ordinary sodium or potassium bicarbonate, urea potassium bicarbonate, and potassium chloride base agents; the second, multipurpose, type contains an ammonium phosphate base. The multipurpose extinguisher can be used on class A, B, and C fires. Most dry chemical extinguishers use stored pressure to discharge the agent, and the fire is extinguished mainly by the interruption of the combustion chain reaction. Foam extinguishers use an aqueous film forming foam (AFFF) agent that expels a layer of foam when it is discharged through a nozzle. It acts as a barrier to exclude oxygen from the fire.

         

IV     EXTINGUISHERS FOR CLASS C FIRES

The extinguishing agent in a class C fire extinguisher must be electrically non-conductive. Both carbon dioxide and dry chemicals can be used in electrical fires. An advantage of carbon dioxide is that it leaves no residue after the fire is extinguished. When electrical equipment is not energized, extinguishers for class A or B fires may be used.

         

V       EXTINGUISHERS FOR CLASS D FIRES

A heat-absorbing extinguishing medium is needed for fires in combustible metals. Also, the extinguishing medium must not react with the burning metal. The extinguishing agents, known as dry powders, cover the burning metal and provide a smothering blanket.

The Underwriters' Laboratories, Inc., has available lists of approved fire extinguishers that may be purchased from different manufacturers. The extinguisher label gives operating instructions and identifies the class, or classes, of fire on which the extinguisher may be used safely. Approved extinguishers also carry the labels of 

the laboratories at which they were tested. 

Fire Safety During Constructions :                                         

1. General:

 Buildings under construction shall be in accordance with this Section.

2. Access Roads:

 Fire Department access roads shall be established and maintained in accordance with Section 902 of this code, as the building is constructed, before it exceeds grade level and before the walls are erected.

2.a Exception:

When approved by the fire chief, temporary access roads of a width, vertical clearance, and surface such as to permit access by fire department apparatus may be permitted only until permanent roads are installed.

3. Gradient:

 The gradient for a fire apparatus access roadway shall not exceed a maximum of 6 percent (6%) unless specifically approved for that site by the fire chief.

4. Water Supply:

 Water mains and hydrants shall be installed and be operational in accordance with Fire Fighting Systems Code, as the building is being constructed, before it exceeds grade level and before the walls are erected.

4.a Exception:

 When approved by the fire chief, a temporary water supply for fire protection may be permitted, pending installation of permanent fire protection systems.

5. Fire Protection:

5.a General:

 During the construction of a building and until the permanent fire extinguishing system has been installed and is in service, fire protection shall be provided in accordance to Section 8704.

5.b Fire Extinguishers:

 Fire Extinguishers shall be provided for buildings under construction when required by the chief. The number and type of extinguishers shall be as required by the chief, and the type of extinguisher shall be suitable for the type of fire associated with the hazards present.

5.c  Standpipes:

5.c.1 Where Required:

 Every building with a floor level that is located more than 55 feet above the lowest level of fire department access or having more than three stories, whichever is less, shall be provided with not less than one standpipe for use during construction. Such standpipe shall be provided with fire department hose connections at accessible locations adjacent to usable stairs and the standpipe outlets shall be located adjacent to such usable stairs. Such standpipe systems shall be extended as construction progresses to within one floor of the highest point of construction having secured decking or flooring.

On each floor there shall be provided one minimum 2-1/2 inch valve outlet for fire department use.

5.c.2 Temporary Standpipes:

Temporary standpipes are allowed to be provided in place of permanent systems if they are designed to furnish 500 gallons of water per minute at 50 pounds per square inch pressure with a standpipe size of not less than 4 inches.

5.c.3 Detailed Requirements:

 Standpipe systems for buildings under construction shall be installed as required for permanent systems.

6. Combustible Debris:

Combustible debris shall not be accumulated within buildings. Combustible debris, rubbish and waste material shall be removed from buildings as often as practical. Combustible debris, waste material and trash shall not be burned on site unless approved.

7. Motor Equipment:

Internal-combustion powered construction equipment shall be used in accordance with the following:

1.     Equipment shall be located so that exhausts do not discharge against combustible material,

2.     When possible, exhausts shall be piped to the outside of the building,

3.     Equipment shall not be refueled while in operation, and

4.     Fuel for equipment shall be stored in an approved area outside of the building.

8. Heating Devices:

Temporary heating devices shall be of a type approved by the chief, located away from combustible materials, and attended and maintained by competent personnel.

9. Smoking:

Smoking shall be prohibited, except in those areas approved by the Chief. When required by the chief, a suitable number and type of NO SMOKING signs shall be posted.

10. Cutting and Welding:

Cutting and welding operations shall be in accordance with the code.

11. Flame-producing Equipment:

The use of torches or flame-producing devices for the sweating of pipe joints shall be in accordance with Article code.

12. Flammable Liquids:

The storage, use and handling of flammable liquids shall be in accordance with Article 79. Ventilation shall be provided for operations utilizing the application of materials containing flammable solvents.

13. Open-flame Devices:

Open-flame devices and other sources of ignition shall not be located in areas where flammable materials are being used.

14. Asphalt and Tar Kettles:

Asphalt and tar kettles shall be located and operated in accordance with this code.

15. Temporary Electrical Wiring:

Temporary electrical wiring shall be in accordance with this code.

16. Building Access:

 When required by the chief, access to buildings for the purpose of fire fighting shall be provided. Construction material shall not block access to buildings, hydrants or fire appliances.

17. Emergency Telephone:

When required by the chief, telephone facilities shall be provided at the construction site for the purpose of emergency notification of the fire department. The street address of the construction site shall be posted adjacent to the telephone together with the fire department telephone number.

18. Fire-protection Plan:

When required by the chief, a fire-protection plan shall be established.

       Fire, heat and light resulting from the rapid combination of oxygen, or in some cases gaseous chlorine, with other materials. The light is in the form of flame, which is composed of glowing particles of the burning material and certain gaseous products that are luminous at the temperature of the burning material. The conditions necessary for the existence of fire are the presence of a combustible substance, a temperature high enough to cause combustion (called the ignition temperature) and the presence of enough oxygen (usually provided by the air) or chlorine to enable rapid combustion to continue.

      Fire has been produced by two principal methods, friction and percussion. In the friction method, friction raises the temperature of a combustible material (kindling) to ignition temperature. The percussion method produces a spark to set kindling afire.

In some cultures people have used and still use chiefly the friction method, in which two pieces of wood surrounded by combustible material are rubbed together until the ignition temperature is reached. In the stick-and-groove method, a stick is rubbed in a groove in another piece of wood. In the fire-drill method, a stick is rotated rapidly in a pit in a stationary piece of wood. The stick is rotated by rubbing it between the palms of the hands or by moving back and forth a wooden bow whose string is wrapped around the stick.

      The most basic percussion method of producing fire is striking together two pieces of flint, or by striking flint against pyrite. Later, steel was substituted for the pyrite. The flint-and-steel method prevailed throughout the civilized world until about 1827, when matches came into use. With matches, friction is used to heat the tip of the match to the point at which chemicals in the match head ignite.

      Fire may also be produced by using a lens or curved reflector to concentrate the rays of the sun on combustible material.

      The use of fire probably developed in four stages. First, people observed about them natural sources of fire, such as volcanoes and trees set afire by lightning. Second, they acquired fire from natural sources and used it for warmth, light, and protection from predators. Third, they learned to make fire whenever they chose. Finally, they learned to control fire for use in smelting metal ore, in baking pottery, and in numerous other ways to help create new technologies and make life more comfortable.

Fire Fighting :

           

             Fire Fighting, techniques and equipment used to extinguish fires and limit the damage caused by them. Fire fighting consists of removing one or more of the three elements essential to combustion—fuel, heat, and oxygen—or of interrupting the combustion chain reaction.

           Most fire fighting consists of applying water to the burning material, cooling it to the point at which combustion is no longer self-sustaining. Fires involving flammable liquids, certain chemicals, and combustible metals often require special extinguishing agents and techniques. With some fuels the use of water may actually be dangerous

Fire Fighting System
Necessity of Fire Fighting system
• The fire fighting system in the sub station is very
essential
• Saves the equipment from damage
• Loss of life & loss of equipment can be prevented
• Regular trial operation of the system is necessary to
detect any fault /deficiency in the system.
Classification of Fire protection system
1. Fire Fighting system
• The extinguishing systems which are normally employed for protection of
various equipments/buildings:
• Portable and mobile fire extinguishers.
• Hydrant system
• High velocity water spray system.
• Sprinkler system
• Medium velocity water spray system
• Water mist system
• Total flooding system using co2.
• Drain and stir type system
1.Fire Fighting System
2. Fire Detection System
Fire detection
Fire detection
Detection of fire at incipient stage plays very important role as it enables in
suppressing the fire by means of the fire fighting equipments and prevent it
from developing in to a major fire.
Detection of fire
- visual (presence of personnel is required to communicate to the concerned
authorities)
-Automatic (with the use of detectors)
Fire Detection system
– This system will provide alarm signal at the initial stage of fire.
– Detectors are located at strategic positions in the area covered by this system.
– Detectors are arranged in zones so that the area of fire can be easily identified.
– If any of the detectors in a zone is actuated an audio cum visual signal will be
given to the control panel
Schematic of Fire Fighting
Hydrant system
• Hose pipes along with branch pipes and nozzles are kept in post
boxes located adjacent to hydrants points
• In case of fire, these hoses are coupled to the respective hydrant and
jet of water is directed towards the seat of the fire.
• The system is automatic to the extent that whenever the pressure in
the piping network drops the beyond a preset value, signal is given
to start the hydrant pump by means of pressure switch. However
the stopping of the pump is manual.
• Water for the hydrant service is generally stored in an easily
accessible RCC reservoir. The water for the hydrant system shall be
supplied from the nearest bore wells available in the substation.
• The Hydrant system is spread in the switchyard and the auxiliary
systems
• Large pipes of dia 300mm/250mm/150mm either underneath or
above the ground runs in the yard
• Identification – post office red painted
• The pressure in the line is maintained by the air compressor in auto
mode – 7Kg/cm2
• The hydro pneumatic tank maintains the pressure and loss of water.
• Jockey pump maintains the water level in the hydro-pneumatic
tank
• Two level switches detect the water level
Hydrant system
Pumps
GENERAL REQUIREMENTS:
• Pumps shall be exclusively used for the fire fighting purposes. The
pumps used for the fire protection system are of the following types
• Electric motor driven centrifugal pumps, or
• Compression ignition engine driven centrifugal pumps or
• Vertical turbine submersible pumps.
– In all the above cases, pumps shall be automatic in action.
– Pumps shall be direct-coupled, except in the case of enginedriven vertical turbine pumps wherein gear drive shall be used
– Belt-driven pumps shall not be used.
Pumps & Motors
• Electrical driven HVWS Pump – 410Cum/Hr Motor 125KW
• Diesel engine driven HVWS pump - 410Cum/Hr Engine 166BHP
• Electrical driven Hydrant Pump – 96Cum/Hr Motor 30KW
• Diesel engine driven HVWS pump - 96Cum/Hr Engine 57BHP
• Jockey pump – 10.8CuM/Hr Motor 7.5KW
• Air Compressor – 8Kg/Cm2 Motor 3KW
High Velocity Water (HVW) Spray System
• This system is used for the protection of transformers and reactors in the
substation.
• The High Velocity Water Spray System - for extinguishing of oil fires
• It is employed to bring about a fundamental change in the nature of the
inflammable liquid, which is converted temporarily into an emulsion which
cannot burn.
• High Velocity water spray system - network of projectors arranged around
the equipment to be protected.
• Water under pressure is directed to the projector network through a flow
control/deluge valve from a pipe network laid exclusively for the spray
system.
• The minimum running water pressure at any projector must in no instance
be below 3.5 bar.
Electrical HVWS / Diesel engine
Emulsification process
• A special type of nozzle – projectors discharges a cone of water in the form
of evenly distributed broken streams of high velocity and high momentum.
• The rapid movement of the broken streams of water is suddenly arrested at
the oil surface and the impact causes the oil to be broken up into tiny
globules to form an emulsion with water.
• In this manner, almost immediately the water from the projector strikes the
burning oil-in-water emulsion is formed which cannot burn.
• In addition, the dispersion of the oil in minute globules in the water gives
almost instantaneous cooling and thus, together with the extinguishment of
the fire, there is simultaneous cessation of the formation of the Vapour
• Detection of fire – Quartzoid bulbs fitted in the detection line
• The Quartzoid bulbs are broken at 79Deg C thus reducing the pressure in
detection line
Deluge Valve system
HVWS Maintenance
Water Spray Systems
WATER SUPPLIES:
• Water for the spray system shall be stored in any easily accessible
surface or under ground lined reservoir or above ground tanks of steel,
concrete, or masonry.
• Reservoirs/tank shall be in two independent but interconnected
compartments with a common sump for suction to facilitate cleaning and
repairs.
• Water for the systems shall be free of particles, suspended matters,etc. and
as far as possible, filtered water shall be used for the systems.
• Level indicator shall be provided for measuring the quantity of water
stored anytime.
• Water reservoir/tank shall be cleaned at least once in two years or more
frequently if necessary to prevent contamination and sedimentation.
• It is advisable to provide adequate inflow into the reservoir/tank so that the
protection can be reestablished within a short period.
Types of fire detectors
• Heat detectors
• Smoke detectors
• Flame detectors
Heat Detectors
• These are generally less sensitive than smoke detectors and are
unlikely to respond for smoldering fires.
• They are not suitable for the protection of places where small fires
can cause huge losses.e.g. Computer Rooms
• These are suitable for use in places where sufficient heat is likely to
be generated and damage caused the heat generated by fire
contributes top main hazards. E.g. Battery Rooms, Boilers etc
Smoke detectors
Two types are available
- Ionization type
- Optical Type
Ionization type :
These are based on the principle that the electric current flowing
between electrodes in an ionization chamber is reduced, when
smoke particles enter the chamber.
Optical type :
These operate by detecting the scattering or absorption of light by
smoke particles.
• Fire detection system is provided in the following areas:
• Control room with false ceiling and floor void)
• Relay room
• DCDB
• Cable vault
• Battery room
• MCC room
• Conference room
• AHU room
If false ceiling is used detectors can be provided above and below the false
ceiling.
Ionization type smoke detectors can be used in all rooms but in cable vault
a combination of ionization and photo-electric type smoke detectors are
recommended.
Smoke detectors shall be equipped with an integral LED which will
glow in the event of its operation.
Portable fire extinguishers
The different type of fire extinguishers and their application:
• Class of fire Suitable extinguisher
Class -A Fire on ordinary combustibles Gas expelled water types and
water buckets
Class-B Fires in flammable liquids, CO2 ,DCP and sand buckets.
paints, grease and solvents.
Class-C Fires in gaseous substances CO2 and DCP type.
under pressure including LPG
Class-D Fires in reactive chemicals Special type of DCP and
active metals. Sand buckets.

A fire fighting system is probably the most important of the building services, as its aim is to protect human life and property, strictly in that order.  

It consists of three basic parts:

• a large store of water in tanks, either underground or on top of the building, called fire storage tanks
• a specialised pumping system,  
• a large network of pipes ending in either hydrants or sprinklers (nearly all buildings require both of these systems)

A fire hydrant is a vertical steel pipe with an outlet, close to which two fire hoses are stored (A fire hydrant is called a standpipe in America). During a fire, firefighters will go to the outlet, break open the hoses, attach one to the outlet, and manually open it so that water rushes out of the nozzle of the hose. The quantity and speed of the water is so great that it can knock over the firefighter holding the hose if he is not standing in the correct way.  As soon as the fire fighter opens the hydrant, water will gush out, and sensors will detect a drop in pressure in the system. This drop in pressure will trigger the fire pumps to turn on and start pumping water at a tremendous flowrate.
A sprinkler is a nozzle attached to a network of pipes, and installed just below the ceiling of a room. Every sprinkler has a small glass bulb with a liquid in it. This bulb normally blocks the flow of water. In a fire, the liquid in the bulb will become hot. It will then expand, and shatter the glass bulb, removing the obstacle and causing water to spray from the sprinkler. The main difference between a hydrant and a sprinkler is that a sprinkler will come on automatically in a fire. A fire hydrant has to be operated manually by trained firefighters - it cannot be operated by laymen. A sprinkler will usually be activated very quickly in a fire - possibly before the fire station has been informed of the fire - and therefore is very effective at putting out a fire in the early stages, before it grows into a large fire.  For this reason, a sprinkler system is considered very good at putting out fires before they spread and become unmanageable.  According to the NFPA of America, hotels with sprinklers suffered 78% less property damage from fire than hotels without in a study in the mid-1980s.

An electric fire pump located in a fire fighting pump room.

FIRE STORAGE TANKS

The amount of water in the fire storage tanks is determined by the hazard level of the project under consideration.  Most building codes have at least three levels, namely, Light Hazard (such as schools, residential buildings and offices), Ordinary Hazard (such as most factories and warehouses), and High Hazard (places which store or use flammable materials like foam factories, aircraft hangars, paint factories, fireworks factories).   The relevant building code lists which type of structure falls in each category.  The quantity of water to be stored is usually given in hours of pumping capacity. In system with a capacity of one hour, the tanks are made large enough to supply the fire with water for a period of one hour when the fire pumps are switched on.  For example, building codes may require light hazard systems to have one hour’s capacity and high hazard 3 or 4 hours capacity.  

The water is usually stored in concrete underground tanks. It is essential to ensure that this store of water always remains full, so it must have no outlets apart from the ones that lead to the fire pumps. These tanks are separate from the tanks used to supply water to occupants, which are usually called domestic water tanks. Designers will also try and ensure that the water in the fire tanks does not get stagnant and develop algae, which could clog the pipes and pumps, rendering the system useless in a fire

FIRE PUMPING SYSTEM

Fire pumps are usually housed in a pump room very close to the fire tanks. The key thing is that the pumps should be located at a level just below the bottom of the fire tank, so that all the water in the tanks can flow into the pumps by gravity.

Like all important systems, there must be backup pumps in case the main pump fails. There is a main pump that is electric, a backup pump that is electric, and a second backup pump that is diesel-powered, in case the electricity fails, which is common. Each of these pumps is capable of pumping the required amount of water individually - they are identical in capacity.

There is also a fourth type of pump called a jockey pump. This is a small pump attached to the system that continually switches on to maintain the correct pressure in the distribution systems, which is normally 7 Kg/cm2 or 100 psi. If there is a small leakage somewhere in the system, the jockey pump will switch on to compensate for it. Each jockey pump will also have a backup.

The pumps are controlled by pressure sensors. When a fire fighter opens a hydrant, or when a sprinkler comes on, water gushes out of the system and the pressure drops. The pressure sensors will detect this drop and switch the fire pumps on. But the only way to switch off a fire pump is for a fire fighter to do this manually in the pump room. This is an international code of practice that is designed to avoid the pumps switching off due to any malfunction in the control system.

The capacity of the pumps is decided by considering a number of factors, some of which are:

• the area covered by hydrants / standpipes and sprinklers
• the number of hydrants and sprinklers
• the assumed area of operation of the sprinklers
• the type and layout of the building

THE DISTRIBUTION SYSTEM

The distribution system consists of steel or galvanised steel pipes that are painted red.  These can be welded together to make secure joints, or attached with special clamps.  When running underground, they are wrapped with a special coating that prevents corrosion and protects the pipe.  

There are basically two types of distribution systems

Automatic Wet systems are networks of pipes filled with water connected to the pumps and storage tanks, as described so far.

Automatic Dry systems are networks of pipes filled with pressurized air instead of water. When a fire fighter opens a hydrant, the pressurized air will first rush out. The pressure sensors in the pump room will detect a drop in pressure, and start the water pumps, which will pump water to the system, reaching the hydrant that the fire fighter is holding after a gap of some seconds. This is done wherever there is a risk of the fire pipes freezing if filled with water, which would make them useless in a fire.
Some building codes also allow manual distribution systems that are not connected to fire pumps and fire tanks. These systems have an inlet for fire engines to pump water into the system. Once the fire engines are pumping water into the distribution system, fire fighters can then open hydrants at the right locations and start to direct water to the fire. The inlet that allows water from the fire engine into the distribution system is called a siamese connection.

In high-rise buildings it is mandatory that each staircase have a wet riser, a vertical fire fighting pipe with a hydrant at every floor.  It is important that the distribution system be designed with a ring main, a primary loop that is connected to the pumps so that there are two routes for water to flow in case one side gets blocked.

In more complex and dangerous installations, high and medium velocity water-spray systems and foam systems (for hazardous chemicals) are used.  The foam acts like an insulating blanket over the top of a burning liquid, cutting off its oxygen.  Special areas such as server rooms, the contents of which would be damaged by water, usegas suppression systems.  In these an inert gas is pumped into the room to cut off the oxygen supply of the fire.

When you design a fire fighting system, remember the following:

• Underground tanks: water must flow from the municipal supply first to the firefighting tanks and then to the domestic water tanks.  This is to prevent stagnation in the water.  The overflow from the firefighting to the domestic tanks must be at the top, so that the firefighting tanks remain full at all times.  Normally, the firefighting water should be segregated into two tanks, so that if one is cleaned there is some water in the other tank should a fire occur.
• It is also possible to have a system in which the firefighting and the domestic water are in a common tank.  In this case, the outlets to the fire pumps are located at the bottom of the tank and the outlets to the domestic pumps must be located at a sufficient height from the tank floor to ensure that the full quantity of water required for fireghting purposes is never drained away by the domestic pumps.  The connection between the two tanks is through the suction header, a large diameter pipe that connects the all the fire pumps in the pump room.  Therefore there is no need to provide any sleeve in the common wall between the two firefighting tanks.
• The connection from each tank to the suction header should be placed in a sump; if the connection is placed say 300mm above the tank bottom without a sump, then a 300mm high pool of water will remain in the tank, meaning that the entire volume of the tank water will not be useable, to which the Fire Officer will object.
• Ideally the bottom of the firefighting pump room should be about 1m below the bottom of the tank.  This arrangement ensures positive suction for the pumps, meaning that they will always have some water in them.
• All pump rooms should without fail have an arrangement for floor drainage; pumps always leak.  The best way to do this is to slope the floor towards a sump, and install a de-watering pump if the water cannot flow out by gravity.
• In cases where there is an extreme shortage of space, one may use submersible pumps for firefighting.  This will eliminate the need for a firefighting pump room.
• Create a special shaft for wet risers next to each staircase.  About 800 x 1500 mm should suffice.  It is better to provide this on the main landing rather than the mid landing, as the hoses will reach further onto the floor.

medical piped system design

Types of medical gas systems

There are two basic types of medical gas systems, namely:

unilateral system:

It is a system that is the pressure to reduce medical gas pressure required at the exits and the beginning of the main station for the supply of various gases.

 binary system:

It is a system that reduce pressure medical gas which is in two phases the first phase takes place in the main station to the top of the exits at the desired pressure and then pressure is then pressure reduction phase

Components of medical gas system

Medical gas systems consist of the following elements:

sources of supply plants or various medical gases.

Distributed gas piping network.

exits medical gases.

 monitoring and warning system.

sources of supply stations and various medical gases

Are sources that supply piping system various medical gases and this element is also divided into several elements are as follows:

• the supply of medical gas cylinders through the station.

• the supply of compressed air station through the air compressors.

• suction through suction pumps station.

First: medical gas supply station through the cylinder

It is designed to extend hospital departments and medical gases (oxygen, nitrous oxide, carbon dioxide, nitrogen). Overall cylinder station consists of two rows of cylinders equal, one of these two grades be in working condition while the other shall be the primary alternative to the class when emptied Alostoanat.oicon automatically switch between grades through autoomatic switch the possibility of switching from row to row the other hand. It must be designed so that the station does not stem the tide of medical gas at the service station or maintenance.

May use liquefied oxygen tanks in large hospitals or when a large consumption rate. Oxygen tanks are insulated tanks containing thousands Turat of liquefied oxygen when evaporation produces oxygen gas multiplier hundreds of times the size of its size it is liquefied. These tanks are placed in special places and each tank there and from which you can fill the empty tin when its piping system, 

Second: The compressed air supply station through the air compressors

Unlike other medical gases, which are supplied through the cylinder, the medical compressed air is usually Antiajh in the hospital itself and that is through the payment of external atmospheric air into the air compressors, which are linked to a network of pipes that supply the various medical departments air after treatment in order to comply with the air specifications Medical where the following conditions must be in the compressed medical air and the output of the station are available:

• oils ratio does not exceed 0.5 mg per cubic meter.

• dew degree of not less than 5 degrees down less unexpected degree of operating temperature.

• Carbon monoxide ratio does not exceed 5 ml per cubic meter.

• carbon dioxide ratio does not exceed 1 000 ml per cubic meter.

Third, the suction through suction pumps station

Suction station of three or more suction pumps consists, tank or more, two or more filters bacteria, a jar exchange or more in addition to the unit for the station control. It must be suction abroad exchange station away from the neighboring buildings and the direction of the wind away from neighboring buildings.

Distributed pipes for gas network

Piping system used for the transmission and distribution of medical gases from gas stations to the exits of the various sections, taking into account the following:

• pipes must bear the pressure equivalent to 1.2 of the maximum possible pressure.

• flexible connections may be used as part of the network so as to prevent transmission of vibration.

• You must reach your piping system grounded in hospital.

• must be the protection of piping system from damage that may result from the collision devices such as Alterolliat and dispute.

• must prove pipes pillars so as not bend or bows out.

• props must be made of corrosion resistant material.

• should not be used for any special props pipes other uses.

•

Portable Air Compressors - Mobile & Portable

(1) SAFETY RELIEF VALVE Every ROLAIR air compressor is equipped with a safety relief valve which is designed to

discharge tank pressure at a predetermined setting when a systems failure occurs. Check the safety valve periodically by

pulling on the ring only when the tank pressure is completely drained. The spring loaded valve should move freely within the

safety valve body. An inoperable safety valve could allow an excessive amount of tank pressure to build causing the air tank to

catastrophically rupture or explode.

Do not tamper with or attempt to eliminate the safety relief valve.

(2) MANUAL OVERLOAD / MOTOR RESET Every ROLAIR electric air compressor is built with manual overload protection. If

the motor overheats, the overload sensor will trip the reset button to protect the motor. If this occurs, please allow the motor to

cool for approximately five minutes. Locate and push in the reset button. The use of an undersized or excessive length of

extension cord may be the cause of overheating. Re-evaluate the power source and gauge/length of extension cord being

used. (Refer to chart on page 8)

(3) PRESSURE SWITCH Most electric air compressors are operated by the use of a pressure switch. Always make sure

the lever is in the off position before plugging in the power cord. By moving the lever to the “On/Auto” position, the compressor

will start and stop automatically within the settings of the pressure switch which are typically 105 – 130 PSI. Do not attempt to

stop the compressor by unplugging the power cord. To stop, simply move the lever to the “Off” position. The lever operates a

relief valve that dumps off head pressure and allows the compressor to restart without load the next time it is used.

(4)REGULATOR – WORKING PRESSURE To adjust the output/line pressure, simply lift up on the regulator adjustment knob

and rotate clockwise to increase working pressure or counter-clockwise to decrease. Push adjustment knob back down to lock

in setting. Never exceed the manufacturer’s maximum allowable pressure rating of the tool being used or item being inflated.

(5) PRESSURE GAUGE(S) Typically, most compressors are designed with a gauge to measure tank or storage pressure

and another gauge attached to the regulator that indicates output or working pressure.

(6) DRAIN VALVE(S) One or more drain valves are installed to allow moisture to be drained on a daily basis from the

compressor storage tank(s). Open drains carefully and slowly to prevent scale, rust, or debris from becoming expelled at a

high rate of speed.

(7) AIR INTAKE FILTER Air intake filters are installed to prevent foreign matter from entering into the engine or

compressor pump. Check intake elements on a regular basis and either clean or replace as needed. Warm soapy water or

low compressed air may be used to clean the elements. Check intake canisters or elbow components for cracks or broken

seals and replace if structural problems are found.

centrifugal pump

A centrifugal pump

converts input power to kinetic energy by accelerating liquid in a revolving device - an impeller.

The most common is the volute pump - where fluid enters the pump through the eye of the impeller which rotates at high speed. The fluid accelerates radially outward from the pump chasing and a vacuum is created at the impellers eye that continuously draws more fluid into the pump.

The energy from the pumps prime mover is transfered to kinetic energy according the Bernoulli Equation. The energy transferred to the liquid corresponds to the velocity at the edge or vane tip of the impeller. The faster the impeller revolves or the bigger the impeller is, the higher will the velocity of the liquid energy transferred to the liquid be. This is described by the Affinity Laws.

Pressure and Head

If the discharge of a centrifugal pump is pointed straight up into the air the fluid will pumped to a certain height -  or head - called the shut off head. This maximum head is mainly determined by the outside diameter of the pump's impeller and the speed of the rotating shaft. The head will change as the capacity of the pump is altered.

The kinetic energy of a liquid coming out of an impeller is obstructed by creating a resistance in the flow. The first resistance is created by the pump casing which catches the liquid and slows it down. When the liquid slows down the kinetic energy is converted to pressure energy. 

• it is the resistance to the pump's flow that is read on a pressure gauge attached to the discharge line

A pump does not create pressure, it only creates flow. The gauge pressure is a measurement of the resistance to flow.

In fluids the term head is used to measure the kinetic energy which a pump creates. Head is a measurement of the height of the liquid column the pump could create from the kinetic energy the pump gives to the liquid. 

• the main reason for using head instead of pressure to measure a centrifugal pump's energy is that the pressure from a pump will change if the specific gravity (weight) of the liquid changes, but the head will not

The pump's performance on any Newtonian fluid can always be described by using the term head. 

Different Types of Pump Head

• Total Static Head -  Total head when the pump is not running
• Total Dynamic Head (Total System Head) - Total head when the pump is running
• Static Suction Head - Head on the suction side, with pump off, if the head is higher than the pump impeller
• Static Suction Lift - Head on the suction side, with pump off, if the head is lower than the pump impeller
• Static Discharge Head - Head on discharge side of pump with the pump off
• Dynamic Suction Head/Lift - Head on suction side of pump with pump on
• Dynamic Discharge Head - Head on discharge side of pump with pump on

The head is measured in either feet or meters and can be converted to common units for pressure - like psi, Pa or bar.

• it is important to understand that the pump will pump all fluids to the same height if the shaft is turning at the same rpm

The only difference between the fluids is the amount of power it takes to get the shaft to the proper rpm. The higher the specific gravity of the fluid the more power is required.

• Centrifugal Pumps are "constant head machines"

Note that the latter is not a constant pressure machine, since pressure is a function of head and density. The head is constant, even if the density (and therefore pressure) changes.

The head of a pump can be expressed in metric units as:

h = (p₂ - p₁) / (ρ  g) + v₂² / (2 g)         (1)

where

h = total head developed (m) 

p₂ = pressure at outlet (N/m²)

p₁ = pressure at inlet (N/m²)

ρ =   density (kg/m³)

g = acceleration of gravity (9.81)  m/s²

v₂ = velocity at the outlet (m/s)

Head described in simple terms

• a pump's vertical discharge "pressure-head" is the vertical lift in height - usually measured in feet or m of water - at which a pump can no longer exert enough pressure to move water. At this point, the pump may be said to have reached its "shut-off" head pressure. In the flow curve chart for a pump the "shut-off head" is the point on the graph where the flow rate is zero

Pump Efficiency

Pump efficiency, η (%) is a measure of the efficiency with wich the pump transfers useful work to the fluid. 

η = P_out / P_in  (2)

where 

η = efficiency (%)

P_in = power input

P_out = power output