QUALITY ASSURANCE INSPECTION PROGRAM

PROGRAM OVERVIEW

TPI field agents visit truss plants on an unannounced basis during normal business hours on a quarterly basis. TPI QC protocol calls for 2 truss designs and a lumber grade stamp check (based on the cut list) at the in-feed side of the component saw to be inspected. All plates, lumber, tooth count, plate mis-location, wood joinery, and assembly are scrutinized for a minimum of 3 trusses. Very often, a 100% check of the plates and lumber for a particular design is possible for the entire setup, if it is under construction or has yet to be banded. If non-conformances are found in any of the first 3 trusses checked, a minimum of 5 trusses are looked at, focusing on the specific non-conforming item(s) found from the previous 3 trusses checked.

It is TPI's experience that additional sampling helps the fabricator determine if the non-conformance(s) was random or consistent in nature. If random, the truss is corrected by the licensee with no additional follow-up by TPI. If consistent, the problem is corrected by the licensee, and a management letter from TPI is usually forthcoming. Typically, consistent (i.e., 20% and greater) non-conformances found throughout the truss design setup is useful information to the fabricator, since it helps alert them to the possibility of retraining personnel, initiating accountability protocols, considering different assembly practices, repairing/recalibrating /replacing equipment, etc. as well as modifying their own in-house quality monitoring by focusing on the problems detected by the TPI audit.

TPI field agents do not follow-up to ascertain whether the deficiencies (random or consistent) were corrected. Very often, if the non-conformance pertains to lower than specified plates or lumber (unauthorized substitution prior to assembly), the fabricator will attempt to re-engineer to avoid a costly repair. Also, ANSI/TPI 1 allows re-engineering to accept fabrication tolerances exceeding ANSI/TPI 1 upon approval and follow-up documentation by a truss designer. A few fabricators will attempt to re-analyze mis-located plates and, to a lesser extent, excessive openness of joints with re-engineering. Nevertheless, re-engineering after assembly does not change a TPI documented non-conformance to a conformance. On the other hand, some plants elect to disassemble the truss, even though re-engineering may accept the substituted material, to make a point with assembly personnel that engineering should not be relied upon to "bail them out for their mistakes."

TPI field reports are forwarded to TPI Headquarters for additional processing and review. If non-conformances are denoted regardless of the percentages, TPI agents must fax field reports to TPI within a few days of the inspection for review by the Director of Inspection Services. Upon review, if consistent non-conformances are detected, the Director of Inspection Services prepares a management letter (confidential communiqué) outlining...1) specific non-conformances per ANSI/TPI 1 and QAP-90; 2) the rating change Alpha => Beta => Theta (monthly inspections) => Suspension; 3) suggestions for correcting the problem; and 4) a request from the truss plant to outline their corrective measures. Licensees may activate an appeals mechanism involving an autonomous review committee to investigate whether a rating change was warranted. If the next unannounced inspection results in conforming trusses or random non-conformances, the rating change is reversed Theta => Beta => Alpha. The vast majority of the licensees reclaim their Alpha rating upon follow-up inspection by TPI.

The inspection forms which are to be used in accordance to the ANSI/TPI 1-2002 National Design Standard & Commentary are now available for viewing.

ANSI/TPI 1-2002 Inspection Formwork - Truss Plant Copy

ANSI/TPI 1-2002 Inspection Formwork - TPI Inspector Copy

Stamp Order Form (PDF)

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