Pre-glazing considerations
When selecting glazing products, specifiers can feel more confident about their specifications if manufacturers have taken certain pre-glazing considerations into account. This includes manufacturers’ shop drawing review, a pre-installation procedures meeting and inspection of the glazing system, and breather or capillary tubes.
For the shop drawing review, project-specific glazing shop drawings or fenestration system details can be submitted to the IGU sealant manufacturer for review. The glass fabricator or manufacturer should also be consulted regarding the glass construction, strength, and compliance with specifications and glazing details. In addition, the sealant manufacturer should be consulted for assurances of sealant compatibility and strength, approval of spacer shim materials, and for recommendations on optimum joint configuration and proper adhesion to glass and support members.
Before installing the glazing, application guidelines from the IGU fabricator, sealant, or other glazing material manufacturers should be reviewed with the on-site glaziers or shop personnel setting the glass in fenestration systems.
As glazing begins, fabrication tolerances should be checked. For example, the glazing should be free of debris and obstructions, weep holes should be open and free of obstructions, and glazing surfaces should be free of moisture, dirt, grease, oil, and other contaminating materials.
Care should be taken that screws, bolts, rivets, and weld fillets do not protrude into the glazing channel which would reduce the minimum required face or edge clearances.
Further, all joinery, connectors, screws or bolt heads, rivets, and water dams should be effectively sealed; all steel or wood glazing rabbets and contact areas of dissimilar materials should be effectively primed; and setting blocks, weep baffles, and edge blocks should be properly located in the glazing channels.
In inspecting the glass, the IGU should be measured for proper dimensions, recognizing fabricator-published tolerances. Also, glass edges, sealant uniformity, and coating quality should be inspected according to the glass manufacturer’s guidelines, as applicable.
For VIG, consider inspection of pillars, or objects that keep the lites from touching, and the pump-out port, or area where the air is pulled to create the vacuum, to make sure they meet the fabricator’s specifications. The fabricator should also set questionable glass aside for inspection. For breather or capillary tubes, consult the IGU fabricator for proper installation procedures.
