Overview
ISO 7737:1986, "Tolerances for building - Presentation of dimensional accuracy data," defines how measured dimensional accuracy data from building construction and manufactured components should be collected and presented. Intended for all types of building construction, the standard sets out the principles and formats for reporting dimensional tolerances so the data can be used directly by designers, manufacturers and contractors as reliable feedback from site and factory surveys.
Key topics and requirements
- Scope and purpose: Lays down principles for collecting and presenting dimensional accuracy data relevant to fit and assembly in building work.
- Statistical presentation: Requires accuracy data to be presented using standard deviation and systematic deviation as the primary parameters describing dimensional variability.
- Assessment of factors: Data sets must be checked for significant influencing factors (e.g., jigs, production method). If a factor is significant, a separate statement of variability is required; otherwise datasets may be combined statistically.
- Measurement items: Specifies types of dimensions to measure, including:
- setting-out dimensions (distances, levels, angles)
- manufactured components (length, width, thickness, squareness, flatness)
- constructed work and erected components (verticality, level, joints, clearances)
- Recording format: Measurement results should be recorded on standardized forms (examples in the standard, e.g., table-based recording forms) that capture reference size, measurement points, material, measurement conditions, and remarks on sources of error.
- Normality and presentation: Guidance on testing for normality of data (histograms where tests are not made or indicate non-normality). Defines formats for generalized accuracy data (aggregated across contractors/manufacturers) and specific accuracy data (single contractor/manufacturer).
- Publication responsibility: Recommends national standards bodies publish generalized accuracy data; specific datasets should be published by the responsible contractor or manufacturer.
Applications and users
ISO 7737 is practical for:
- Building designers - to select component reference sizes and jointing techniques with known probabilities of satisfactory fit.
- Component manufacturers - to set target sizes for widest applicability and predict fit with constructed work.
- Contractors and site managers - to plan remedial measures, assess economic impact of misfits, and control workmanship.
- Quality and measurement teams - to standardize measurement recording and statistical reporting for audits and continuous improvement.
Keywords: ISO 7737, dimensional tolerances, dimensional accuracy data, building construction, standard deviation, systematic deviation, measurement format, construction surveying.
Related standards
- ISO 3443 (Tolerances for building-basic principles and statistical basis)
- ISO 7976 (Methods of measurement of buildings and building products)
- ISO 5479 (Normality tests)