Order of Council re Petroleum Acts - Order in Council re Explosives Acts - Home Office Conditions for Acetylene Generators - English Acetylene Associations' Regulations.

Legislation relating to Calcic Carbide and Acetylene.

Early in 1897 an Order of Council was issued placing carbide of calcium under the Petroleum Acts, not with any intention of hampering the industry, but with the object of bringing before the notice of the public that in the use of the new illuminant, acetylene, and in the employment of carbide of calcium, from which it is evolved, reasonable precautions would have to be taken. This action of the Home Department cannot be too strongly commended, and if it seems to some that it may have retarded the development of the industry, it must also be borne in mind that the injury of persons by avoidable accidents would have retarded it still more, and it is satisfactory to note that in this country we have not had to deplore such accidents as have occurred abroad. It is true that these accidents were chiefly due to the storage of liquefied acetylene in cylinders under very high pressures, the use of which is prohibited in this country, still, but for legislation, similar accidents would probably have occurred here.

The public, hearing of these accidents through the Press, could not of course be expected to distinguish between liquid acetylene, stored at a pressure of 700 lbs. to the square inch, and gaseous acetylene at low pressure, which with ordinary care can be quite safely generated in properly constructed apparatus.

By an Order in Council of November, 1897, acetylene gas, when liquid or when highly compressed, was very properly brought under the Explosives Acts, hut with the proviso that if it could be shown to the satisfaction of the Secretary of State that acetylene in any form or condition was not explosive, an exemption might be granted.

Exemption was subsequently granted for certain admixtures of acetylene and oil-gas on the initiative of the Acetylene Illuminating Company.

British Home Office Committee of 1901, dealing with the conditions which an Acetylene Generator should fulfil before it can be considered as being safe.

1. The temperature in any part of the generator, when run at the maximum rate for which it is designed, for a prolonged period, should not exceed 130° C. This may be ascertained by placing short lengths of wire, drawn from fusible metal, in those parts of the apparatus in which heat is liable to be generated.

2. The generator should have an efficiency of not less than 90 per cent. which, with carbide yielding 5 cubic feet per pound, would imply a yield of 4.5 cubic feet per each pound of carbide used.

3. The size of the pipes carrying the gas should be proportioned to the maximum rate of generation, so that undue back pressure from throttling may not occur.

4. The carbide should be completely decomposed in the apparatus so that lime sludge discharged from the generator shall not be capable of generating more gas.

5. The pressure in any part of the apparatus, on the generator side of the holder, should not exceed that of 20 ins. f water, and on the service side of same, or where no gas-holder is provided, should not exceed that of 5 ins. of water.

6. The apparatus should give no tarry or other heavy condensation products from the decomposition of the carbide.

7. In the use of a generator regard should be had to the danger of stoppage of passage of the gas and resulting increase of pressure which may arise from the freezing of the water. Where freezing may be anticipated steps should be taken to prevent it.

8. The apparatus should be so constructed that no lime sludge can gain access to any pipes intended for the passage of gas or circulating of water.

9. The use of glass gauges should be avoided as far as possible, and, where absolutely necessary, they should be effectively protected against breakage.

10. The air space in a generator before charging should be as small as possible.

11. The use of copper should be avoided in such parts of the apparatus as are liable to come in contact with acetylene.* of water, are necessary in certain generators and without danger, the Executive may, with the approval of the Home Office, grant exemptions for such generators, with or without conditions.

The English Acetylene Association has drawn up the following list of regulations, which it suggests shall govern the construction of generators: -

1. The temperature of the gas immediately on having the charge shall not exceed 212° F. (100° C).

2. Machines shall be so constructed that when used in accordance with printed instructions it shall not be possible for any undecomposed carbide to remain in the sludge removed from the generator.

3. The limit of pressure in any part of the generator shall not exceed that of 20 ins. of water, subject to the exception that if it be shown to the satisfaction of the Executive of the Acetylene Association that higher pressures, up to 50 ins.

* This refers evidently to pare copper and not to its alloys. - Author.

4. The limit of pressure in service pipes within the house shall not exceed 5 ins. of water, subject to the exception that if it be shown to the satisfaction of the Acetylene Association that for certain purposes a higher pressure, up to 10 ins. of water, is necessary, the Executive may authorise such higher pressure to be used for such purposes.

5. The apparatus shall give no tarry or other heavy condensation products from the decomposition of the carbide.

6. In the use of a generator regard shall be had to the danger of stoppage of passage of the gas and resulting increase of pressure which may arise from the freezing of the water. Where freezing may be anticipated steps shall be taken to prevent it.

7. It shall not be possible under any conditions, even by wrong manipulation of cocks, to seal the generating chamber hermetically.

8. It shall not be possible for the lime sludge to choke any of the gas-pipes in the apparatus nor water-pipes, if such be alternately used as safety-valves.

9. The use of glass gauges shall be avoided as far as possible, and where absolutely necessary they shall be effectively protected against breakage.

10. The air space in the generator before charging shall be as small as possible, i.e., the gas in the generating chamber shall not contain more than 8 per cent. of air half a minute after commencement of generation. A sample of the contents drawn from the holder, any time after generation has commenced, shall not contain an explosive mixture, i.e., more than 18 per cent. of air. This shall not apply to the initial charges of the gas-holder, when reasonable precautions are necessary.

11. Generators and apparatus shall be made of sufficiently strong material and of good workmanship, and shall not in any part be constructed of unalloyed copper.

12. Generators shall have sufficient storage capacity to make a serious blow-off impossible.

13. Wherever the generating plant is situated sufficient ventilation must always be provided.

A blow-off pipe shall, wherever desirable, be affixed leading from the gas-holder to the open air.

14. The Association strongly advise the use of an efficient purifier with generating plant for indoor lighting.

15. No generator shall be sold without a card of instructions suitable for hanging up in some convenient place. Such instructions shall be of the most detailed nature, and shall not presuppose any expert knowledge whatever on the part of the operator.

16. Every generator shall have marked clearly upon the outside a statement of the maximum number of half-cubic-foot burners and the charge of carbide for which it is designed.