Sources & methodology

Entries are reference material: structured summaries of dimensions, practices, standards, people, buildings and related knowledge. They are organised for search and comparison, not as a replacement for the full text of a code, standard, manufacturer sheet or academic publication.

Sources are listed on each entry so you can verify figures against the applicable document. Perspecq does not claim that every figure has been independently re-measured or re-certified by The 7th Perspective. Treat entries as a map to authoritative records.

Technical values often depend on the country or code family in force. Perspecq tags entries with one or more jurisdictions and defaults the interface to International / General, while still supporting the United States, the United Kingdom, Europe / EU, Australia, Canada, and international / general reference.

Code-dependent information should always be checked against the adopted code of your authority having jurisdiction. Model codes (NBC India, IBC, Approved Documents, Eurocodes) are frequently amended locally. Typical practice is not necessarily a legal requirement.

• IndiaNBC, BIS / IS codes, CPWD
• United StatesIBC, IRC, ADA, ASHRAE
• United KingdomApproved Documents, BS
• Europe / European UnionEurocodes, EN standards
• AustraliaNCC, AS/NZS
• CanadaNBC Canada, CSA
• ChinaGB, JGJ codes
• JapanBSJ, JIS
• East AsiaRegional reference
• Southeast AsiaRegional reference
• South AsiaRegional reference
• Middle EastRegional reference
• AfricaRegional reference
• Latin AmericaRegional reference
• International / GeneralISO and broadly accepted practice

Use the region control in the header to prioritise matching material in search and category lists. International references remain available alongside a regional filter.

Images are sourced separately from entry text and are used only where a visual materially improves understanding. Where a photograph or archival image is used, Perspecq stores and displays the following provenance for every image:

• Image sourceA link to the original source page where the image is published (typically a Wikimedia Commons file page or an institutional archive).
• Image creatorThe photographer, artist or institution credited by the source, where available.
• Image licenceThe stated licence (for example CC BY-SA, CC0 or Public domain) under which the image is reused.
• Attribution textA ready attribution line combining creator, licence and source, displayed on the entry page.

Perspecq does not claim ownership, authorship or originality over third-party photographs or illustrations, and does not present external imagery as works of The 7th Perspective. Where a suitable, openly licensed image cannot be verified, the entry carries no image rather than a placeholder.

Perspecq distinguishes between several kinds of source so that the basis of each figure is clear:

• Official standards and codesPrimary regulatory documents (NBC India, IS codes, IBC, Eurocodes, ADA, ISO) that carry legal or model-code weight in their jurisdiction.
• Jurisdictional sourcesThe authority having jurisdiction whose adopted code or bye-law governs a code-dependent value, identified per entry where practical.
• Information sourcesPublished reference works, textbooks and manufacturer data from which a reference or typical-practice value is drawn.
• Secondary referencesEncyclopaedic, archival or institutional sources used for historical and biographical entries, cited so the reader can consult the original.

Perspecq makes useful information easier to discover; it does not replace authoritative sources. Where a value is jurisdiction-dependent, the entry names the applicable jurisdiction and the reader must verify against the adopted local code.

Users should verify critical information against authoritative sources before relying on it for design, construction, compliance or professional decisions. See the Disclaimer for the knowledge-sharing notice.