4. The carbide must be kept in closed watertight vessels, so as to ensure perfect dryness and only such quantities shall be taken out as are needed. The vessels must be kept in dry, light, well-ventilated rooms; cellar rooms may not be used for storage purposes.
5. Crushing of carbide must be done with the greatest possible avoidance of dust. Workers are to be provided with respirators and goggles.
6. Acetylene gasometers must be fitted up in the open air or in a well-ventilated room, separated from the gas generator. Every gas receiver must have a water gauge showing the pressure in the receiver.
7. Between the gasometer and receiver a gas purifier must be provided so as to remove impurities (phosphoretted hydrogen, arseniuretted hydrogen, carbon bisulphide, ammonia, &c.).
8. Condensation of acetylene gas at a pressure exceeding ten atmospheres shall only be done in combination with cooling.
Distribution and Use of Power and Illuminating Gas
The Austrian Gas Regulations (of July 18, 1906) contain general provisions as to impermeability and security of the gas pipes and the precautions to be observed in their installation. Special directions follow as to main flues, material, dimensions, branches, and connections, valve arrangements, testing of the pipes against leakage, directions for discovering leaks, and other defects; also the nature of the branch pipes (dimensions and material), valves, cocks, syphons, water seals, and pressure gauges. In addition there are directions as to testing pipes and how to deal with escape of gas, freezing of pipes, and other mishaps.
Ammonia
(See also pp. [90-3] and [175])
In the production of ammonia and ammonium salts (ammonium sulphate) combination of the ammoniacal vapour with the sulphuric acid is accompanied with the formation of volatile dangerous gases containing sulphuretted hydrogen and cyanogen compounds, which produce marked oppression and sometimes endanger the health of the workers. Drawing-off these fumes into the furnace (practised sometimes in small industries) is not advisable, as the sulphuretted hydrogen is burnt to sulphur dioxide; if it is burnt absorption of the sulphur dioxide should follow, or working it up into sulphuric acid (Leymann). Often these gases are freed from cyanogen compounds and sulphuretted hydrogen by means of gas purifying materials, such as are used in gas works. The whole apparatus must be impervious. Where liquids containing ammonia are used exhaust ventilation is necessary.