Monday, March 12, 2012

Regulations Pertaining to Storage, Usage of Hazardous Chemicals

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Various chemicals, flammable liquids and gases are extremely, important to our modern way of life and constitute a major volume of present day commerce. Billions of gallons of highly’ flammable liquids and hazardous chemicals are manufactured and marketed with a high degree of safety. On the other hand many fires leading to injury and death result from improper storage and use of flammable liquids, especially in and around the house or in small business premises. The difference lies in realizing how hazardous the materials are and the application of safe procedures.

Factors Determining Severity of Hazards

1. How the chemical is used.
2. Type of job operation (how the workers are exposed).
3. Work pattern. large_chemical_storage
4. Duration of exposure.
5. Exposed liquid surfaces.
6. Evaporation rate.
7. Pattern of air flow.
8. Operating temperature.
9. Concentration of vapor in work, room.
10. Ventilation efficiency.
11. Housekeeping.

Persons responsible or connected with storage and handling of chemicals should be made aware of the hazards involved. All containers should be labeled properly with diamond shaped hazard symbol and chemical data sheet mentioning the properties of the chemicals in short. so that immediate steps can Ix: taken in case of any spillage of the container.

Chemical Data Sheet

1. Name

2. Properties

a. Physical
b. Chemical


3. Uses

4. Hazards

a. Personal health
b. Fire and explosion
c. Control measures


5. Storage and handling

6. Personal protective equipment

7. a. Toxicity
b. T.L.V.


8. Symptoms of poisoning

9. First aid

10. Waste disposal

Hazardous Chemicals

Chemicals can be divided into three classes:
1. Chemicals which in no way support or assist combustion these are silicates, carbonates, bicarbonates. phosphates, chlorides. bromides, iodides, sulphates, sulphites, sulphides, thiosulphates, higher halogenated compounds.

2. Chemicals which are themselves combustible these arc organic compounds like cellulose, sugars, proteins, resins. petroleum, etc.

3. Chemicals which produce oxygen for burning: In this group come nitrates, chlorates, perchlorates, per-magnates, chromates, dichromates and organic nitrates.

For reasons which can be understood, chemicals from group 2 must not come in contact with chemicals from group 3. While stocking chemicals in godowns it is necessary to know the incompatibles those which react exothermically with one another. Some of these incompatible chemicals are:

1. Acid chemicals vs. basic ones: e.g. free acids like hydrochloric, sulphuric, acetic acids or chemicals like potassium bisulphate, against bases like ammonia, lime, soda, metal oxides, etc.,

2. Ammonium salts vs. basic oxides or carbonates: These will react, may be with tragic end.

3. Bleaching powder vs. turpentine: Bleaching powder liberates chlorine which reacts exothermically with ammonia, ammonium carbonate or unsaturated organic substances like turpentine oil or linseed oil. This may be a source of fire.

Flammable Materials

In the organization of safer y measures against fire hazards, careful consideration has 10 he given to the siting and design of stores, material handling procedure etc. Various substances particularly flammable liquids and loose packing materials, provide a ready source or fire. In addition absence of adequate storage arrangement mar also cause congestion on the factory floor thus indirectly adding to the fire risk by concealing an outbreak at the initial stages and obstructing access to the fire, to the alarm point, to the extinguishing equipment and to the escape routes.

For indoor storage of combustible material, a detached building, specially designed for the purpose, is the safest arrangement from the fire protection point of view. The building should be protected by an automatic sprinkler installation or automatic fire alarm. Provision should be made as far as possible for the segregation of all goods according to their fire hazard, so that precaution appropriate to each category can be taken. In any case, the storage building should be subdivided by a fire resistant construction so as to provide compartments to which fire may be confined to, should an outbreak occur.

Goods should be stocked in such a way that they are easily accessible. There should be adequate separation between stacks and base areas of stacks should be as small as possible. Individual stacks or piles should nor be so high as to be beyond easy reach of fire fighters. In any case the space between the ceiling and the top of the goods must not be less than one foot. In buildings protected by automatic sprinklers, goods should not be stacked within one foot of sprinkler heads. Racks and shelves should be, wherever possible, made of noncombustible materials.

Solid Storage

Then planning storage arrangements for solids, both the nature and the form of the material should be taken into account. Solid materials may enter or leave the plant in bags, drums or bulk carrier. These may be stored in their own containers, in hoppers or silts, or bulk piles, either indoors or outdoors.

Flammability of the material must be established to determine the safe size and spacing of storage units and the design basis for the electric and fire protection systems. The possibility of spontaneous combustion, either in bulk piles or piles of bags may limit the safe depth of storage.

If stored in the open, these should be arranged in a number of separate piles with no point in each pile more than 10ft, in height. Occasional temperature measurements of such piles may be required. Susceptibility to dust explosions will determine the grounding equipment that will be required.

Bins for the, storage of pulverized material should be of noncombustible material and so located that radiation from boilers, furnaces, steam pipes or other sources of heat cannot raise the temperature of the contents to a dangerous degree.

Fine metallic powders can be pyrophoric and these should be stored in air tight containers. Oxidizing agents like chlorates can explode violently in contact with organic materials. Care should be taken to keep such materials in a segregated area. Metals like sodium, potassium, etc. react violently with water giving rise to flames. These materials must be stored away from water.

Liquids Storage

Liquids are generally received or shipped in drums, carboys, tank cars or trucks or by pipeline. They may be stored in their shipping containers or in ranks.

While dealing with flammable liquids, it should be kept in mind that it is the vapour from the evaporation of the liquid rather than the liquid itself that burns or explodes when mixed with air in the presence of a source of ignition. According to Petroleum Rules 1976, inflammable liquids art classified into three classes i.e Class A, B and C depending on the flash point as given below:

Class A Flash
point below 230C

Class B Flash
point not below 230C but below 650C

Class C Flash
point not below 650C but below 930C

Liquids with flash pints below 320C (900F) are liable to give off ignitable vapor's at normal ambient temperatures. Such liquids may be stored in closed containers and in limited quantities in rooms of fire resisting construction which are situated above the ground and isolated from the reminder building by fire walls and self closing fire doors.

Large quantities of such liquids shall be stored in isolated buildings of fire resisting construction or in outdoor storage tanks preferably underground.

The rooms should not have openings covered with glass or transparent material which would allow the direct rays of the sun to pass.

Same precautions should be taken for liquids with flash points between 32 660C (90 1500F), particularly in tropical countries where the ambient temperatures arc likely to be high during summer months.

When stored in room, It should be thoroughly ventilated at the floor as well as at the ceiling level to remove vapor's which might accumulate from leaking containers. The room should be further provided with special trapped f1oor drainage facilities and explosion relief in the form of pressure opening windows or a weak wall, providing 1sq. foot of venting for ever y 50 cu ft. of room volume.

Electrical, fittings in areas where flammable liquids and solvents arc handled and stored should be of flame proof and vapor proof type.

Adequate arrangements for quickly draining any spillage should be provided in all areas. However, attempts should be made to minimize the liquid going into the sewer, as its vapor may cause fires and explosions in lines.

While storing in drums, these should nor be filled fully with liquid. About 5: space should be left for vapor's. Drums should be stored with bungs on top to avoid leakage of material.

The minimum distance specified for storing highly flammable liquids from plants is 30 ft, but from residential area it should be 100 ft. The distance also depends on the quantity and quality of the hazardous material being stored. The relevant authority for us is the Indian Explosives Act and Petroleum Act.

Gas Storage

Flammable gases should be stored separately from each other and from other goods. It should be borne in mind that nonflammable gas cylinders are also capable of exploding if heated.

Cylinders containing compressed gases may only be stored in the open if they an: adequately protected against excessive variation of temperature, direct rays of the sun, accumulation of snow or continuous dampness.

United Nations Hazard Classification

United Nations
Division
Hazard Type
1
Explosives
1.1
Mass explosion hazard
1.2
Projection hazard but not mass explosion hazard
1.3
Fire hazard and minor blast or projection hazard
1.4
No significant hazard
1.5
Very insensitive substances hazard
2
Gases
3
Flammable liquids
3.1
·         Flash point below IMDG 3oC (closed cup) Code*
·         flash point below 18oC (closed cup)
3.2
·         Flash point between 23 and 60.50C (close cup)
·         IMDG Code, flash point between 0 and 230C (closed cup)
3.3
IMDG Code flash point between 23 and 60.5*
(closed cup)
4
Flammable solids
4.1
Flammable solids
4.2
Substances liable to spontaneous combustion
4.3
Substances emitting flammable gases in contact
with water
5
Oxidizing substances
5.1
Oxidizing substances other than organic
5.2
Organic Peroxides
6
Poisonous (toxic) and infectious substances
6.1
Poisonous (toxic) substances
6.1.1
Substances emitting toxic vapours
6.1.2
Poisonous substances other than those emitting
toxic vapor’s
6.2
Infectious substances.
7
Radioactive substances.
8
Corrosive substances.
9
Miscellaneous dangerous substances.
* International Maritime Dangerous Goods Code

Characteristic Background Colour of Label:

Explosive
Orange
Flammable
Red
Water reactive
Blue
Oxidizer
Yellow
Toxic or Infectious
White
Radioactive
White or Yellow
and White
Corrosive
Black and White

An additional diamond with a black exclamation point is used to denote Class 9 in U.K. only.
When such cylinders are stored inside industrial establishments the storage spaces should be isolated from the other areas by fire resisting and heat resisting walls or partitions. Compressed gases should never be stored 1eat highly flammable substances or near any source of heat.

Responsibility for Safety

The operating department must be held responsible for emptying washout, steaming out, purging with inert gas and other steps to make equipment safe before it is turned over for maintenance or repair work. Maintenance personnel has the responsibility of making sure proper blanking off of pipelines, ventilation and testing for flammable vapours at the time of actual starting of maintenance or repair work. During shutdown and startups special care must be taken to see that all lockout and tagging procedures are followed closely for electrical work, for moving machinery and valves etc.

Entering Vessels and Confined Spaces

The following actions are to be taken before entering any confined space (Sec. 36 of the Factories Act, 1948).

Preparation of Equipment

1. Pumping out and draining all the liquid from the container.

2. Thorough cleaning

3. Sampling of all to prove absence of toxic or noxious vapor and presence of sufficient oxygen (at least 16 percent volume).

4. Men who enter vessels must be equipped with safety belts and life lines. For ease in lifting, belts should be fitted high under armpits and not around waist.

5. Airline apparatus supplying fresh air and PVC suit may be required in most of the cases.

6. The manhole should be of 22"; in extreme case 1lr’ opening may be allowed. Rope or chain ladders with rigid rungs are to be provided for entry.

Isolation of Equipment from Hazards

1. All power driven devices such as agitators must be locked out at positive disconnect switches.
2. Blinding or positively segregating connected pipeline from all possible sources of hazardous liquid, gas or steam. All the blinds which have been inserted must be listed so that these can be removed after the
work is completed.
3. Tagging and locking all related valves and switches. Each group of workers shall use their own tagging and locking devices and shall themselves be responsible for removing them.

Preventive Maintenance

Unplanned maintenance is always carried out under sudden pressure causing accidents and injury due to some short curs taken to complete the job within a short specified time. With a view to avoid sudden breakdown and unscheduled down time, inspection, repair and replacement of equipment must be carried out on an intelligently planned schedule. Apart from tremendous cost advantages, the advantages to safety are obvious as the trouble spot will be located well in advance and exposure to emergency condition will be reduced to minimum.

Preventive maintenance implies preventing emergency repairs; still some emergency does occur and we must plan to take care of it well in advance and not after it happens. Planning should include emergency kit and personnel so that everyone knows who should do what, how and with what, if the situation calls for.

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