Effects of Thermal Shrinkage on Built-up Roofing

Effects of Thermal Shrinkage on Built-up Roofing
Author: William C. Cullen
Publisher:
Total Pages: 12
Release: 1965
Genre: Roofing, Bituminous
ISBN:
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The effects of thermal movement of bituminous built-up roof membranes are related to some common failures of built-up roofing observed in field exposures.A procedure for determining the amount of thermal movement of built-up membranes is described.Data are given for the thermal movement of various bitumens and reinforcing felts used in the con * struction of built-up roofs and for the composite membranes over a temperature range construction of built-up roofs and for the composite membranes over a temperature range of +30 to -30F.The data obtained are related to field experience and suggestions are presented which will prove beneficial in reducing the incidence of built-up failure due to thermal movement.(Author).

Laboratory-field Comparisons of Built-up Roofing Membranes

Laboratory-field Comparisons of Built-up Roofing Membranes
Author: Thomas H. Boone
Publisher:
Total Pages: 20
Release: 1968
Genre: Roofing
ISBN:
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The values of breaking load, elongation and thermal expansion of nine bituminous built-up membranes prepared by roofing contractors under field conditions and by technicians in the laboratory were measured at sub-freezing temperatures.The data indicated that the field-prepared specimens agreed favorably with laboratory-prepared specimens, although the samples from the field frequently reflected higher values for thermal-shock resistance than did their laboratory-prepared counterparts.The higher values were attributed to the smaller amounts of bitumen used between the plies of the field specimens.The results appeared to support the validity of the application of the 'strength-thickness rule' to bituminous built-up membranes.(Author).

Thermal-shock Resistance for Built-up Membranes

Thermal-shock Resistance for Built-up Membranes
Author: William C. Cullen
Publisher:
Total Pages: 28
Release: 1967
Genre: Building materials
ISBN:
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The resistance of bituminous built-up roofing membranes to thermally induced forces is considered in terms of their strength properties such as breaking load in tension, modulus of elongation and apparent linear thermal expansion coefficient.The development of a Thermal-Shock Resistance Factor is described and values are given for three bituminous built-up membranes at temperatures of - 30F (-34.4C), 0F (-17.8C), 30F (-1.1C) and 73F (22.8C).The apparent relation between the values obtained in the laboratory and the observed performance of roofing membranes in service is considered.The utilization of the Thermal-Shock Resistance Factor in the reduction of potential failures of bituminous built-up roofing membranes in service from thermally induced forces is also discussed.(Author).

Investigation of the Hydraulics of Horizontal Drains in Plumbing Systems

Investigation of the Hydraulics of Horizontal Drains in Plumbing Systems
Author: Robert S. Wyly
Publisher:
Total Pages: 520
Release: 1964
Genre: Drainage, House
ISBN:
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Results are reported from an investigation of the hydraulics of flow in experimental apparatus simulating nominally horizontal simple and branching drains of plumbing systems. The data are correlated with limited findings in an earlier, unpublished NBS study the results of which have been utilized in current plumbing codes. The need for further research is pointed out, particularly in relation to hydraulic performance of drain systems as affected by steep slopes, drain storage volume, energy losses at stack bases, attenuation of water depths and discharge rates in long drains, and large drain diameters.