Sweet’s indexed catalogue of building construction for the year 1906 (1906)
New York : Chicago : Architectural Record · leaf 554
in, thusallowing air to pass freely through the Valve. The Norwall Automatic Air and Vacuum Valve is a mechanical device scien-tifically correct, and is designed for use in buildings heated by low pressure steam, es-pecially in connection with residence work, stores and small apartments where…
Building materials
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