Quality concepts
Tolerance
Also called: tolerances
A tolerance is how much a real, built condition is allowed to differ from the specified value and still pass — the plus-or-minus around a dimension, a slope, a level or a flatness. Nothing in the field is ever exact, so specs and standards set the band within which the work is still good. A tolerance is one of the most concrete forms an acceptance criterion takes: it turns "level enough" into a number you can measure against.
Why it matters
Tolerance is where craft meets the tape measure. A floor that looks flat can still bust a flatness tolerance, and a slab set a fraction low can throw off everything stacked on it. Knowing the allowable band before you place work is what keeps small variances from becoming a nonconformance.
It also settles disputes. When the criterion is a stated tolerance, a measurement and a photo decide the question — the work is inside the band or it is not.
Common mistakes
Treating a target as a hard line and rejecting work that is comfortably within tolerance, or the reverse — waving through a drift that is actually outside the band because it "looks close." Either way the fix is to measure against the stated tolerance, not the eye.
Standards it's verified against
Checklists that put tolerance to work
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related terms
- Acceptance criteriaThe stated, measurable conditions installed work has to meet before it can pass — the yardstick an inspection judges against.
- DefectA flaw in materials or workmanship that makes the work fall short of what was specified or of accepted trade practice.
- NonconformanceInstalled work that does not meet the drawings, spec or accepted submittal — formally identified so it gets dispositioned, not ignored.
- Quality control (QC)The hands-on inspection and testing of installed work against the spec — checking the actual product, not the process that made it.
- Quality assurance (QA)The planned system of procedures, plans and checkpoints set up before work starts so the right result is built the first time.
- DeficiencyWork that is incomplete, missing or not up to standard — the catch-all a punch list and inspections use for anything that still needs attention.
Knowing the term is step one. Proving it is the job.
RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.