1850.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



321 



to such a house for worship, or other galleried building, than in 

 one which has no gallery, and which possesses the advantage of an 

 open roof; and those who would object to the copious measures 

 here recommended, as unnecessary, should well consider the follow- 

 ing facts and calculations. A chapel or meeting-house with large 

 galleries nearly all round, capable of accommodating on special 

 occasions 2000 persons, is frequently made about 75 feet square, and 

 25 feet average height, giving a total cubic content of rather more 

 than 140,000 feet. Now the authorities, from Tredgold to Reid 

 who have written on the subject of the quantity of fresh air, 

 required per minute by each individual, to replace that which such 

 individual has rendered unfit for respiration, vary in their conclu- 

 sions from Sj to 10 cubic feet; and if seven cubic feet be assumed 

 to be the proper quantity, an allowance near the average of their 

 scientific opinions will he given. The total quantity required, 

 therefore, on this low standard in such a building, to maintain its 

 atmosphere in a state of purity when filled, will be (2000 X 7 :=) 

 14,000 cubic feet every minute, and a like quantity of vitiated air 

 must be carried off in the same time. The atmosphere of the 

 building will therefore require to be completely changed or renewed 

 (140,000 -j- 14,000 = 10) once in every ten minutes. Let it now be 

 supposed that the unusual provision of 16 openings has been made 

 all round the building, for fresh air, each opening measuring 18 

 inches by 6 inches. Deducting one-third of the area for impedi- 

 ment caused by gratings, will allow to each opening a clear area of 



/A///yyA 



■ ■'''^' 



a, Fire-box J f, Ash-box; c, Smolse-box ; d. Fire-bars: e. Smoke-tubes j 

 /, Fuel-box; g, Damper; h, Flow or steam-pipe; i, Return or condensation 

 pipe ; i, Ash-box door ; k, Fire-door ; /, Smolte-pipe, 



half a superficial foot, and the aggregate area of all the openings 

 will be eight feet. Now, to supply the required quantity of air 

 (14,000 cubic feet) in the given time (one minute) through those 

 openings, the air must pass through them all at the velocity of 

 (14,000 -7- 8 =) 1750 feet per minute, or more than twenty miles 

 per hour; which it will not do, especially on a calm day in hot 

 weather, when ventilation is most needed, without the aid of some 

 powerful stimulus; and if such artificial impulse be wanting, those 

 openings will, under the circumstances, be quite insufficient to 

 prevent the rapid deterioration of the atmosphere within, and 

 ought, therefore, to be considerably enlarged. The bad effects of 

 the usual way of obtaining a partial supply of air in such a case 

 by opening the windows, have been already commented on. 



"Take another e.xample from a large Gothic church, with galleries, 

 and lofty side aisles and nave, in the neighbourhood where this is 

 written; measuring 80 feet by 65 feet, with a roof approaching to 

 flatness, about 30 feet in average height. This church has often 

 contained 1800 persons; its cubic contents being 156,000 feet, and 

 the requirement of air, allowing, as before, seven feet per minute 

 to each person (1800 X 7 =) 12,600 feet. The time in which the 

 whole atmosphere of this church would, when containing its full 

 complement of persons, require to be changed, is (156,000 

 -r- 12,600 =) 12| minutes; and large openings wlU obviously be 

 required to pass the quantity in the time. 



" These figures will suffice to show the necessity for a very much 

 larger provision for ventilation than has been customary in build- 

 ings containing galleries, in which the cubic contents bear a small 

 proportion to the numbers assembled." 



"The management of the warming of a church being a matter 

 frequently entrusted to a sexton or verger charged with other 

 duties, which necessitate his making a clean appearance, and 

 demand his exclusive attention during the service, it is a matter of 

 some importance where hot-water apparatus are used, to adopt 

 such form of boiler as will require the smallest possible attention. 

 Tlie kind shown in fig. 2 in the annexed section, will be found to 

 fulfil this requirement; many large churches having been kept 

 by it at a uniform temperature with only three attendances in 

 twenty-four hours. This sort of boiler will be found very desir- 

 able in many other buildings besides churches. They are to be 

 filled to the top with coke broken into small jpieces, which falls 

 on the fire as required. A very useful kind of Arnott stove has 

 been largely adopted on the same principle." 



The stove here described appears to us a very simple arrange- 

 ment for effecting the purposes desired, and to be well worthy of 

 adoption. 



In the whole range of ventilation there is, perhaps, nothing so 

 much neglected as the ventilation of schools; and as it is most 

 desirable public attention should be turned to the subject, we most 

 willingly give room to Mr. Walker's statement of his views on the 

 subject: — 



"Schools are freqently very crowded, 

 and their atmosphere in a most unwhole- 

 some condition. The great increase in 

 their number in the populous manufactur- 

 ing districts, is a gratifying sign of the 

 times, and affords good reason to hope 

 that the succeeding generation will grow 

 up with improved ideas and habits, and, 

 as is most needful in those districts, stand 



Fig. 3. 



i-'LJ^ 



i 



some degrees higher than their predecessors in the scale of civi- 

 lisation, 



43 



