The review of submittal data for the project, such as shop drawings, work samples, test and other performance data about the materials to be used, Letters of Certification etc., is one of the first steps of the quality control process. Whether the information received from subcontractors and suppliers for items to be installed into the project meets the standards set forth in the contract documents has to be verified. Items such as dimensions (thickness, length, shape), ASTM (American Society for Testing Materials) standards, test reports, performance requirements, color, and coordination with other trades should be reviewed and verified. Particularly crucial is the checking of shop drawings, which fill in information concerning requirements for concrete reinforcement, structural steel, cabinets/millwork, and elevators that may be missing from contract drawings This caveat applies especially for projects using items originally fabricated off-site: the information provided on the approved shop drawings ia what the fabricators use to "custom – make" their materials. Each item on the shop drawings must be verified against the contract plans and specifications. Following meticulous review of the submittal data, a determination is made on whether the project meets the required quality control standard.
Submittals are reviewed by the General Contractor, then given to the consultant engineer for further review. If the data is "disapproved" or incomplete, the originator of the submittal data must resubmit corrected or additional information. A submittal that completes the review process provides the "template" on which additionally-required materials will be fabricated. Any mistakes not discovered in the submittal review process could potentially cause problems involving extra cost and additional time for correction.
The Kansas City Hyatt Regency walkway collapse in 1981 illustrates how a poor shop drawing review can lead to disastrous consequences. A change in the details of structural connections, left unchecked during the submittal process, doubled the load on the fourth floor walkway connections. This led to the collapse of the fourth floor suspended walkway onto the second floor walkway and then onto the ground floor below. This disaster killed 114 and inflicted a further 200 injuries.