Design and Implementation of a Pressure-Equalizing Vent System for Low-Slope Roofs

Winds create forces on buildings, sometimes with disastrous results. Low-slope roofs are subjected to potentially high levels of suction pressure, especially when winds strike the corner of a building, creating vortices. Traditional methods of attaching roof membranes to substrates are prone to failure when the low pressure on the roof surface instigates a transfer of forces to the roof membrane. Existing pressure-equalized roof systems use the power of the wind to transmit low pressure to the space immediately beneath the roof membrane, pulling the membrane down to the roof surface. The object of this study is the design of a wind vent which, when coupled with a single-ply roof membrane in a complete roof assembly, will successfully equalize low pressure throughout the entire field of the roof. The proposed wind vent differs from existing equalizer valves in its use of the Bernoulli effect to create low pressure. Optimized for ease of manufacturing and installation, the vent is omni-directional and contains no moving parts. After the wind vent prototype is developed, future study will be required to determine the tributary area of each vent, the interaction with the insulation beneath the membrane, the response time of the system when subjected to dynamic wind loading, the effect on the vent of various weather conditions, and the permissible amount of infiltration into the roof system. Associated research will also investigate the benefits of incorporating the heat evacuating capacity of the pressure-equalizing roof vent system into a roof membrane containing an amorphous photovoltaic array.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Architecture

Department dc:contributor.department

Architecture

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2003

Author dc:creator

• Grant, Elizabeth J.

Chair dc:contributor.committeechair

• Jones, James R.

Committee members dc:contributor.committeemember

• Telionis, Demetri P.
• Dorsa, Edward A.

• Pressure-equalizing roofing system
• vented roofing system
• vacuum roofing system
• negative pressure roofing system

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-09052003-154559

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/34928