NGS Logo png

#NGS National Green Specification
A Specification for the 21st Century

replacement website is coming (preview)

GBE Logo def_tr40 png

GBE Green Building Encyclopaedia
One stop shop for environmental construction know-how

Search: PAGES or FILES

01733 238148  0044 1733 238148
07973 281024 •  0044 7973 2810248 
Scribd facebook Skype = BrianSpecMan
Twitter = @BrianSpecMan Murphy 
Daily Additions & Updates
Daily Monthly and Quarterly NGS News & Diary

2014 CAPEM logo EU investing png


#1773: 22/05/2015: TGR Steering Group Meeting in Bristol

Dropping students work off at LSBU on the way GBE 3D View on the way ready for Vision London presentation
RSS Icon


Or Equivalent

Or Equivalent


"There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey."

John Ruskin (1819-1900)

With the growth in Design and Build, Construction Management, Management Contracting and their many hybrids, I have seen changes in specification practice, which are eroding the position of the designer and the quality of the end building. Increasingly the requirements and methods of these procurement methods have filtered their way back to General Contracting and it has become more commonplace for Contractors to offer alternative products to those specified, usually offering potential savings.

If there is a project budget or cost plan for the building and tenders are within these figures then there should be no need to consider alternatives. Potential savings may be offered but it will be up to the QS, if there is one, to ensure the savings find their way to the final sum not just the contractor's profit margin.

'Or Equivalent Approved'

Since 1956 LEEDSFORD V CITY OF BRADFORD Case law the use of the term ‘or otherwise approved’ in a specification does not mean the designer must consider alternatives offered by the contractor, nor that the designer must give a reason for not considering alternatives offered.

Many European Directives and their implementing national legislation, in particular the Construction Products Directive (CPD) and the Building Regulations (Regulation 7) were published or updated in the years leading up to or following 1992 when the United Kingdom formally joined the European Market.

Whilst the terms 'or similar' & 'or equal' were in common use for decades leading up to 1992, the term 'or equivalent' began to have greater significance in European Law and in particular related to government financed 'Public Works' projects.


The term 'or equivalent' was in use in standard specifications in particular in PSA General Specification and NBS National Building Specification Preliminaries.
OR OTHERWISE APPROVED did not suggest equivalency,
OR SIMILAR is a weak term by comparison with 'or equal' and should be avoided,
OR EQUAL sounds okay and is okay in UK on non-government projects,
OR EQUIVALENT has greater meaning in EU legal definitions, in EU directives and the UK national legislation implementing them. It is required on all Government financed 'Public Works'.
But OR EQUIVALENT can mean same performance but a different way to achieve that performance,
e.g. roof slate v clay tile, so its also important to control appearance and profiles too.
OR EQUIVALENT AND APPROVED is not strictly necessary but a useful reminder and APPROVED needs also to be defined, it is in NBS preliminaries.

here be dragons

However OR EQUIVALENT AND APPROVED can be problematic when a contractor substitutes without the CA's knowledge and the CA signs-off stage payments for work containing substituted and potentially inadequate materials, is effectively approving the inadequate materials without knowing it.
So its back to OR EQUIVALENT and no more.

The term 'or equivalent' needs definition and ground rules and NBS Clause A31/200 does just that. It requires any proposed substitutions to be notified to the Contract Administrator (often but not always the Architect) submitting evidence in the form of English language test results, certificates, specifications, details, guarantees, etc. These must show equivalency of materials, safety, reliability, appearance, durability, function, of products and all accessories, etc.

WREN PII Insurance

BrianSpecMan hears through providing NGS CPD IN-HOUSE that Specifiers are required to state 'Or equivalent' in every product clause in government work. This encourages substitution and is read by contractors as permission to substitute and substitute surruptitiously.  We think this is a dangerous precedent that will undermine the specification and potentially reduce the quality of the building, but comply with EU rules as interpreted by insurers interpreting case law.

© ASWS NGS, BrianSpecMan aka Brian Murphy
2003 - 27th July 2013

Or Equivalent


© BrianSpecMan aka Brian Murphy
3rd March 2013 - 27th July 2013

Or Equivalent:
See Also:




© BrianSpecMan aka Brian Murphy
10th February 2013 - 27th July 2013