66 VETERINARY HYGIENE 



COMPARISON BETWEEN FIRECLAY AND IRON PIPES AND FITTINGS. 

 The use of cast-iron for drain pipes and fittings certainly possesses 

 some advantages over fireclay. Many of the faults, however, found 

 with fireclay are not inherent defects but due rather to bad material, 

 bad workmanship and bad supervision. The laying of fireclay 

 pipes undoubtedly calls for more supervision than for iron pipes. 



If the pipes are good, free from cracks and faults, the joints 

 properly filled, and the pipes laid in cement concrete where the 

 ground is soft, the result will be satisfactory. Fireclay pipes when 

 well laid are always cleaner than iron drains and will in ordinary 

 circumstances remain practically tight for long periods; on the 

 other hand iron pipes will remain perfectly tight for long periods 

 but do not remain for any length of time perfectly clean. For 

 drains under or in close proximity to habitations iron fittings possess 

 many advantages, especially tightness, and the fact that much better 

 fittings in the way of branches, accesses, bends, traps, &c., can be 

 obtained in iron than in fireclay. For long lines removed from 

 habitations fireclay is quite good. It has, however, always to be 

 borne in mind that, owing to the greater length of iron pipes, 

 fewer joints are required than with fireclay pipes. 



THE LAYING OF DRAINS. In laying drain pipes and fittings in 

 a trench great care must be taken to see that the trench has a good 

 firm bottom, and that it is not made up with loose earth. If the 

 soil immediately underneath the piping is of a loose nature, subsid- 

 ence is bound to occur and considerable strain thrown upon sections 

 of the pipes, so that either the joints become loosened and imperfect 

 or the pipes may actually fracture. The obvious result of such a 

 settlement is that the soil becomes saturated with sewage matter, or 

 sewer gases escape into the soil with probably dangerous conse- 

 quences. Such defects are, of course, not discovered until harm 

 has been done, which draws attention to the probable leakage. In 

 order that the body of the pipe can lie flat on the bottom of the 

 trench, a slight excavation is necessary to receive the faucet. In 

 filling the trench great care must be taken to see that the pipes do 

 not get displaced. The finest of the earth must be used for the first 

 filling and be carefully rammed in to prevent rolling of the pipes. 

 The rougher material containing stones should be put in later as 

 there is then less chance of stones fracturing the fireclay when they 

 are rammed down. If the soil is of a loose character it is well to 

 make a good solid bed of concrete for the pipes to lie on, and with 

 fireclay pipes, especially if running under buildings, the whole pipes 

 may be surrounded with cement concrete. This is, however, an 

 expensive business, and entails much labour and difficulty in getting 



