Location. A stack may be installed inside the building; for instance, all along the rear,[286] or side or front. A small stack is often a feature of a large department room. But generally it occupies an ell or wing of the building, of light construction, projecting from the rear, or from one side.
Where the building must face a noisy street there seems to be no reason why the stack, rather than reading rooms, should not be located there. Why could it not be designed, even if “true stack windows” would make it look like an organ front, as a distinctive architectural feature?
“The stack may be as refreshing a problem for the hard-witted architect to struggle with as he is liable to meet. It may be that the reading rooms will be within, shut off from every noise, and the stack arranged along the exterior.”—Russell Sturgis.[287]
The reading room is now often put just over the stack, as a top-story, separated from it by a solid floor, but connected with it by service tubes, telephones and lifts. But in colleges, is it not better to use such a location for seminar rooms, and in many libraries could it not be used as part of an exhibition and special library or special study floor?
The Stack Shell. That is to say, the addition in which the stack is housed. As has been said, it usually projects from the rear (but sometimes from the side) of the main building, as an ell or wing. It can be of lighter, simpler and plainer construction than the rest, for it needs no other strength than is necessary to support its own walls and roof. Indeed, it has not yet been the victim of architectural ostentation. On the exterior, true stack windows usually run up and down the whole height, although they may be interrupted by cross sections at the level of the floors or decks, or rather just above them.
From recent experiments I have made in a stack, I am led to think that here, as elsewhere, top light from windows is ten times more valuable for penetration than bottom light, hence such a cross-section of wall, about a foot wide, if it has any binding power, strengthens the wall, gives space inside for heating pipes, or looks better, would not abstract any illumination from the interior. Perhaps, however, the piers do not need such binding. That is a question for the architect, and depends largely on their construction. If they are re-enforced by iron or steel T-beams, the piers need not be massive or be strengthened otherwise.
Some authorities (Champneys,[288] for instance) recommend solid floors every three decks, as guard against spread of fire, but this extra expense, not needed for support, seems to me unnecessary as protection.
The material of stacks must be iron, or better, steel, to support so much weight. The construction, indeed, is much like that of a “sky scraper,” whose steel frame stands alone, without help from the walls.
Use by Readers. It does not seem either possible or desirable to plan for continuous use of any space in stacks by readers. The temperature both in summer and winter is usually not so equable as in other rooms. The main object of the stack, which is book storage, is just so much frustrated by surrender of shelf space to readers. But there is much inconvenience in excluding them entirely.