Don'ts .... Don'ts .... Don'tsDon't use water for extinguishing fires in the vicinity of live electrical wiring / apparatus. Don't touch person who is in contact with live circuit but immediately cut off supply of circuit. Don't touch any electrical wires / appliances with wet hands. Don't use fuse in neutral wire. Don't overload wires / appliances. Don't insert direct wires in plug but use appropriate sockets/ pins. Don't attend any fault of our line but immediately inform our local fault center. Don't plant tree under / near electrical lines or equipments. Don't remove /damage or brake electrical lines stays, supports. Don't climb trees which are near electrical lines. Don't bind cloth hanging ropes with any electrical lines, stays, supports to avoid accidents. Don't attend any fault in your premises yourself but do it by licensed electrical contractor.
Friday, November 25, 2011
ELECTRICAL SAFETY DOs AND DONOTs
Install safety equipments for Earth leakage/Over load and Short circuit protection.
Please see that wiring of your premises is done through licensed electrical contractor only as per rules.
Follow up / observe all safety precautions to avoid electrical accidents.
Use always ISI mark appliances, equipments, cables, wires, switches, protective devices etc.
Make any construction by keeping clearance from electrical lines as prescribed in relevant act/ rules.
Use proper capacity fuse wire and ensure healthy earthings at the your premises.
In case of any fault / damage in our electrical lines / equipments, please inform local office immediately and don't touch any live part thereof.
In case of electrical accident, turn off supply and remove person from circuit immediately. immediately. Shift person to hospital and mean while give artificial respiration and primacy treatment.
Advice kids for not to climb kites from electrical lines or supports in any circumstances and to fly kites in open area away from electric lines.
Keep away yourself, kids & your animals from electrical lines, supports, stays etc.
Please keep yourself away from making illegal connections by "Langariya" strictly.
Use rubber hand glows while work with electrical circuits / equipments.
Always keep fire extinguishers in order in residential complex / commercial complex / factories.
Ensure that supply is turned off in case of repairing / replacing lamps or appliances.
Use separate and insulated earth wire.
Keep plugs from away of children's reach. Don't keep plugs open.
Please connect all appliances / equipments by 3 pin plug - sockets.
Assume each circuit live until it is tested and confirmed that it is dead.
Install main switch, Earth Leakage Circuit Breakers, fuses and any protective devices at easily accessible place so it can be turned off in case of any emergency.
Educate your children for not to play with plugs, sockets, wires or other electrical equipments.
Saturday, November 19, 2011
PERMITS AND CLEARANCES FOR ANY PROJECT INSTALLATION SUBJECT TO REQUIREMENT
Permits & Clearances relating to:
- Water allocation and permission for construction of water facilities.
- Power Evacuation transmission approvals for transmissions & distribution of power.
- Railways connectivity permission including construction of railway siding.
To facilitate, develop & maintain relations with external agencies including:
- Mantralaya & Other Departments
- Irrigation Department
- Raw Water Department
- MoEF
- Labour Department
- Commercial Tax Department
- District Industries Center
- SIDC
- SEB
- PCB
- PWD
- PHED
- Food department
- Ground water
- WRD
- Mining
- Forest
- Chief Inspector of Boiler
- Chief Inspector of Explosives
- Airport Authority of India
- National Highway Authority of India
- All other departments
Thursday, November 17, 2011
Wednesday, November 9, 2011
I have talked about the “Five-Whys” technique in some of my classes. It is an excellent technique for root cause analysis. It can take you from surface symptoms to underlying cause. The “Five-Whys” is useful because of the following reasons:
Help identify the root cause of a problem.
Determine the relationship between different root causes of a problem.
One of the simplest tools; easy to complete without statistical analysis. (http://www.isixsigma.com/index.php?option=com_k2&view=item&id=1308&Itemid=200)
The“Five-Whys” are particularly useful in situations that involve human factors or interactions. They can be used outside of the Six Sigma context.
The term “Five-Whys” is not intended as a literal term. A team might need more or less than five whys to tunnel down to the root cause of a problem. When starting the process, it is important not “lead” the questioning to a preconceived “why.” (http://www.qualitytrainingportal.com/resources/problem_solving/problem-solving_tools-5whys.htm)
While the “Five-Whys” is a very useful tool, it does have some limitations. The brainstorming storming required to do “Five-Whys” is time-consuming when compared to other methods. This method can be particularly arduous for larger groups.
The results garnered from the brainstorming used in the “Five-Whys” technique may vary according to group and are difficult to reproduce. Even after the process has been followed, the root causes may not be identified. There is no means to verify that the root causes were identified. (http://www.oshatrain.org/notes/2hnotes10.html)
This post is laced with excellent resources and I have provided a link to a template that is helpful to use with this technique.
5 Whys Template
Tuesday, November 8, 2011
PROPERTIES OF REFRIGERANT
Required Properties of Ideal Refrigerant:
1) The refrigerant should have low boiling point and low freezing point.
2) It must have low specific heat and high latent heat. Because high specific
heat decreases the refrigerating effect per kg of refrigerant and high latent
heat at low temperature increases the refrigerating effect per kg of
refrigerant.
3) The pressures required to be maintained in the evaporator and condenser
should be low enough to reduce the material cost and must be positive to
avoid leakage of air into the system.
4) It must have high critical pressure and temperature to avoid large power
requirements.
5) It should have low specific volume to reduce the size of the compressor.
6) It must have high thermal conductivity to reduce the area of heat transfer in
evaporator and condenser.
7) It should be non-flammable, non-explosive, non-toxic and non-corrosive.
8) It should not have any bad effects on the stored material or food, when any
leak develops in the system.
9) It must have high miscibility with lubricating oil and it should not have
reacting properly with lubricating oil in the temperature range of the system.
10) It should give high COP in the working temperature range. This is
necessary to reduce the running cost of the system.
11) It must be readily available and it must be cheap also.
Important Refrigerants:
Properties at -150C
(1) Ammonia (NH3)(R-717)
Latent heat = 1312.75 kJ/Kg
Specific volume = 0.509 m3/kg
(2) Dichloro–Difluoro methane (Freon–12) (R-12) [C Cl2 F2]
Latent heat = 162 kJ/Kg
Specific volume = 0.093 m3/kg
(3) Difluoro monochloro methane – or Freon-22 (R-22) [CH Cl F2]
Latent heat = 131 kJ/Kg
Specific Volume = 0.15 m3/kg.
The ideal refrigerant has favorable thermodynamic properties, is unreactive chemically, and safe. The desired thermodynamic properties are a boiling point somewhat below the target temperature, a high heat of vaporization, a moderate density in liquid form, a relatively high density in gaseous form, and a high critical temperature. Since boiling point and gas density are affected by pressure, refrigerants may be made more suitable for a particular application by choice of operating pressure. These properties are ideally met by the chlorofluorocarbons.
Corrosion properties are a matter of materials compatibility with the mechanical components: compressor, piping, evaporator, and condenser. Safety considerations include toxicity and flammability.
Refrigerants may be divided into three classes according to their manner of absorption or extraction of heat from the substances to be refrigerated:
Class 1: This class includes refrigerants that cool by phase change (typically boiling), using the refrigerant's latent heat.
Class 2: These refrigerants cool by temperature change or 'sensible heat', the quantity of heat being the specific heat capacity x the temperature change. They are air, calcium chloride brine, sodium chloride brine, alcohol, and similar nonfreezing solutions. The purpose of Class 2 refrigerants is to receive a reduction of temperature from Class 1 refrigerants and convey this lower temperature to the area to be air-conditioned.
Class 3: This group consists of solutions that contain absorbed vapors of liquefiable agents or refrigerating media. These solutions function by nature of their ability to carry liquefiable vapors, which produce a cooling effect by the absorption of their heat of solution. They can also be classified into many categories.
Main article: List of refrigerants
The R-# numbering system was developed by DuPont and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon. The meaning of the codes is as follows:
Adding 90 to the number gives three digits which stands for the number of carbon, hydrogen and fluorine atoms, respectively.[9]
Remaining bonds not accounted for are occupied by chlorine atoms.
A suffix of a lower-case letter a, b, or c indicates increasingly unsymmetrical isomers.
As a special case, the R-400 series is made up of zeotropic blends (those where the boiling point of constituent compounds differs enough to lead to changes in relative concentration because of fractional distillation) and the R-500 series is made up of so-called azeotropic blends. The rightmost digit is assigned arbitrarily by ASHRAE, an industry organization.
For example, R-134a has 2 carbon atoms, 2 hydrogen atoms, and 4 fluorine atoms, an empirical formula of tetrafluoroethane. The "a" suffix indicates that the isomer is unbalanced by one atom, giving 1,1,1,2-Tetrafluoroethane. R-134 (without the "a" suffix) would have a molecular structure of 1,1,2,2-Tetrafluoroethane—a compound not especially effective as a refrigerant.
The same numbers are used with an R- prefix for generic refrigerants, with a "Propellant" prefix (e.g., "Propellant 12") for the same chemical used as a propellant for an aerosol spray, and with trade names for the compounds, such as "Freon 12". Recently, a practice of using HFC- for hydrofluorocarbons, CFC- for chlorofluorocarbons, and HCFC- for hydrochlorofluorocarbons has arisen, because of the regulatory differences among these groups.
R407C pressure-enthalpy diagram, isotherms between the two saturation linesR-401A is a HCFC zeotropic blend of R-32, R-152a, and R-124. It is designed as a replacement for R-12.[10]
R-404A is a HFC "nearly azeotropic" blend of 52 wt.% R-143a, 44 wt.% R-125, and 4 wt.% R-134a. It is designed as a replacement of R-22 and R-502 CFC. Its boiling point at normal pressure is -46.5 °C, its liquid density is 0.485 g/cm3.[11]
R-406A is a zeotropic blend of 55 wt.% R-22, 4 wt.% R-600a, and 41 wt.% R-142b.
R-407A is a HFC zeotropic blend of 20 wt.% R-32, 40 wt.% R-125, and 40 wt.% R-134a.[12]
R-407C is a zeotropic hydrofluorocarbon blend of R-32, R-125, and R-134a. The R-32 serves to provide the heat capacity, R-125 decreases flammability, R-134a reduces pressure.[13]
R-408A is a zeotropic HCFC blend of R-22, R-125, and R-143a. It is a substitute for R-502. Its boiling point is -44.4 °C.[14]
R-409A is a zeotropic HCFC blend of R-22, R-124, and R-142b. Its boiling point is -35.3 °C. Its critical temperatiure is 109.4 °C.[15]
R-410A is a near-azeotropic blend of R-32 and R-125. The US Environmental Protection Agency recognizes it as an acceptable substitute for R-22 in household and light commercial air conditioning systems.[16] It appears to have gained widespread market acceptance under several trade names.[17]
R-500 is an azeotropic blend of 73.8 wt.% R-12 and 26.2 wt.% of R-152a.
R-502 is an azeotropic blend of R-22 and R-115.
Air as a refrigerant"Air cycle is not a new technology. At the turn of the century air cycle or 'cold air machines' were available from companies such as J & E Hall... These were used on board ships and by food producers and retailers to provide cooling for their food stores."[18]
Air has been used for residential,[19] automobile,[18] and turbine-powered aircraft[20][21] air-conditioning and/or cooling. The reason why air is not more widely used as a general-purpose refrigerant is the misperception that the use of air is too inefficient to be practical.[19]
Yet, with suitable compression and expansion technology, air can be a practical (albeit not the most efficient) refrigerant, free of the possibility of environmental contamination or damage,[19] and almost completely[22] harmless to plants and animals.
Corrosion properties are a matter of materials compatibility with the mechanical components: compressor, piping, evaporator, and condenser. Safety considerations include toxicity and flammability.
Refrigerants may be divided into three classes according to their manner of absorption or extraction of heat from the substances to be refrigerated:
Class 1: This class includes refrigerants that cool by phase change (typically boiling), using the refrigerant's latent heat.
Class 2: These refrigerants cool by temperature change or 'sensible heat', the quantity of heat being the specific heat capacity x the temperature change. They are air, calcium chloride brine, sodium chloride brine, alcohol, and similar nonfreezing solutions. The purpose of Class 2 refrigerants is to receive a reduction of temperature from Class 1 refrigerants and convey this lower temperature to the area to be air-conditioned.
Class 3: This group consists of solutions that contain absorbed vapors of liquefiable agents or refrigerating media. These solutions function by nature of their ability to carry liquefiable vapors, which produce a cooling effect by the absorption of their heat of solution. They can also be classified into many categories.
Main article: List of refrigerants
The R-# numbering system was developed by DuPont and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon. The meaning of the codes is as follows:
Adding 90 to the number gives three digits which stands for the number of carbon, hydrogen and fluorine atoms, respectively.[9]
Remaining bonds not accounted for are occupied by chlorine atoms.
A suffix of a lower-case letter a, b, or c indicates increasingly unsymmetrical isomers.
As a special case, the R-400 series is made up of zeotropic blends (those where the boiling point of constituent compounds differs enough to lead to changes in relative concentration because of fractional distillation) and the R-500 series is made up of so-called azeotropic blends. The rightmost digit is assigned arbitrarily by ASHRAE, an industry organization.
For example, R-134a has 2 carbon atoms, 2 hydrogen atoms, and 4 fluorine atoms, an empirical formula of tetrafluoroethane. The "a" suffix indicates that the isomer is unbalanced by one atom, giving 1,1,1,2-Tetrafluoroethane. R-134 (without the "a" suffix) would have a molecular structure of 1,1,2,2-Tetrafluoroethane—a compound not especially effective as a refrigerant.
The same numbers are used with an R- prefix for generic refrigerants, with a "Propellant" prefix (e.g., "Propellant 12") for the same chemical used as a propellant for an aerosol spray, and with trade names for the compounds, such as "Freon 12". Recently, a practice of using HFC- for hydrofluorocarbons, CFC- for chlorofluorocarbons, and HCFC- for hydrochlorofluorocarbons has arisen, because of the regulatory differences among these groups.
R407C pressure-enthalpy diagram, isotherms between the two saturation linesR-401A is a HCFC zeotropic blend of R-32, R-152a, and R-124. It is designed as a replacement for R-12.[10]
R-404A is a HFC "nearly azeotropic" blend of 52 wt.% R-143a, 44 wt.% R-125, and 4 wt.% R-134a. It is designed as a replacement of R-22 and R-502 CFC. Its boiling point at normal pressure is -46.5 °C, its liquid density is 0.485 g/cm3.[11]
R-406A is a zeotropic blend of 55 wt.% R-22, 4 wt.% R-600a, and 41 wt.% R-142b.
R-407A is a HFC zeotropic blend of 20 wt.% R-32, 40 wt.% R-125, and 40 wt.% R-134a.[12]
R-407C is a zeotropic hydrofluorocarbon blend of R-32, R-125, and R-134a. The R-32 serves to provide the heat capacity, R-125 decreases flammability, R-134a reduces pressure.[13]
R-408A is a zeotropic HCFC blend of R-22, R-125, and R-143a. It is a substitute for R-502. Its boiling point is -44.4 °C.[14]
R-409A is a zeotropic HCFC blend of R-22, R-124, and R-142b. Its boiling point is -35.3 °C. Its critical temperatiure is 109.4 °C.[15]
R-410A is a near-azeotropic blend of R-32 and R-125. The US Environmental Protection Agency recognizes it as an acceptable substitute for R-22 in household and light commercial air conditioning systems.[16] It appears to have gained widespread market acceptance under several trade names.[17]
R-500 is an azeotropic blend of 73.8 wt.% R-12 and 26.2 wt.% of R-152a.
R-502 is an azeotropic blend of R-22 and R-115.
Air as a refrigerant"Air cycle is not a new technology. At the turn of the century air cycle or 'cold air machines' were available from companies such as J & E Hall... These were used on board ships and by food producers and retailers to provide cooling for their food stores."[18]
Air has been used for residential,[19] automobile,[18] and turbine-powered aircraft[20][21] air-conditioning and/or cooling. The reason why air is not more widely used as a general-purpose refrigerant is the misperception that the use of air is too inefficient to be practical.[19]
Yet, with suitable compression and expansion technology, air can be a practical (albeit not the most efficient) refrigerant, free of the possibility of environmental contamination or damage,[19] and almost completely[22] harmless to plants and animals.
Sunday, November 6, 2011
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