Measurement practice

Standard codes and methods of measurement

The New Rules of Measurement NRM2: Detailed measurement for building works was published in 2012 as a replacement for the Standard Methods of Measurement of Building Works, which has been used by quantity surveyors for preparing bills of quantities and work packages since 1922. NRM2 became effective on 1 January 2013.

RICS property measurement

In May 2015 RICS published the professional statement RICS property measurement, 1st edition.

The practice of property measurement has changed as follows:

The RICS professional statement RICS property measurement, 1st edition (May 2015), updates the RICS Code of measuring practice (6th edition) and incorporates International Property Measurement Standards (IPMS). The measurement of office buildings and other property types have now been separated and comprise the following 3 elements:

Part 1 - professional statement: office measurement

Professional statements (PS) set out mandatory requirements for RICS members. The RICS professional statement for measuring offices is mandatory from 1 January 2016. RICS members undertaking office measurements must be able to demonstrate compliance if called upon by RICS Regulation. Further guidance on how this professional statement is regulated can be found on the RICS website. www.rics.org

Part 2 - international standards – IPMS: Office Buildings

International standards are developed and implemented collectively by professional institutions, they are not owned by any one entity. Recognised across international markets, these standards are mandatory for RICS members from 1 January 2016. The generic terms used by IPMS: Office Buildings are:

  • IPMS 1, which would equate closely to the former GEA (gross external area).
  • IPMS 2 – Office, which would equate closely to the former GIA (gross internal area).
  • IPMS 3 – Office, which would equate closely to the former NIA (net internal area), sometimes also referred to as net lettable area, net usable area, carpet area or other descriptions.

The IPMS definitions do not correspond exactly to the former GEA, GIA and NIA definitions (see below) and reference should be made to section 4 of the RICS property measurement PS.

Part 3 - Code of measuring practice, 6th edition (2007)

This code should now be used for the measurement of property except offices.

The RICS Code of measuring practice, 6th edition (2007) suggests that the expected reported area figures for high value office space be accurate to within +/–1%. Since 2007, with increased property values this figure may be considered conservative and it is anticipated that in many situations a higher level of accuracy will be achievable and may be desirable. Where measurements taken are used as a basis for valuation, members must have regard to the current edition of the RICS Valuation – Professional Standards (the Red Book) dealing with ethics, competency, objectivity and disclosure. The Code of measuring practice (6th edition) is now global, with effect from 18 May 2015, and provides guidance to professionals on the measurement of all property types except office buildings, which are covered by the professional statement for the measurement of office buildings. The information set out within the Code represents best practice and RICS strongly advises its use by members.

RICS Code of measuring practice

The purpose of the Code is to provide succinct, precise definitions to permit the accurate measurement of buildings (except offices) and land, the calculation of the sizes (areas and volumes) and the description or specification of land and buildings on a common consistent basis. The Code is now global and includes three core definitions that are used in a variety of situations as noted:

Gross external area (GEA)

This approach to measurement is recommended for:

  • building cost estimation for calculating building costs for residential property for insurance purposes;
  • town planning applications and approvals; and
  • rating and council tax bands.

Gross internal area (GIA)

This approach to measurement is recommended for:

  • building cost estimation;
  • marketing and valuation of industrial buildings, warehouses, department stores;
  • valuation of new homes; and
  • property management - apportionment of services charges.

GIA is the area of a building measured to the internal face of the perimeter walls at each floor level.

Net internal area (NIA)

This approach to measurement is recommended for:

  • marketing and valuation of; shops and supermarkets and offices;
  • rating shops; and
  • the apportionment of services charges in property management.

NIA is the usable area within a building measured to the internal face of the perimeter walls at each floor level.

When using the NIA method the following common practice should be noted when measuring to the internal face of the external walls; perimeter heating or air conditioning units should be fixed at a sufficient height to allow a waste paper bin to be placed beneath them, see below, this way the area below the units is deemed to be usable and capable of being let. If the waste bin does not fit then the area below the perimeter unit is excluded from the net internal area; commonly referred to as the ‘waste bin test.’

Figure 1: Waste bin test

Standard Methods of Measurement of Building Works (SMM)

The Standard Method of Measurement first appeared in 1922 and was based on 'the practice of the leading London quantity surveyors'. It was an attempt to bring uniformity to the ways by which quantity surveyors measured and priced building works. The 7th edition appeared in 1988 as a joint publication between the RICS and the Building Employers Confederation and was revised in 1998.

RICS has replaced SMM7 with a new method of measurement for both bills of quantities and work-package measurement. In addition to NRM2, the complete New rules of measurement suite comprises:

RICS NRM 2 came into effect on 1 January 2013.

New rules of measurement NRM2: Detailed measurement for building works

In 2003 the RICS Quantity Surveying and Construction Professional Group commissioned a report ‘Measurement based procurement of buildings’ from the Building Cost Information Service. The report confirmed that measurement still had an important part to play in the procurement of buildings, but it found that measurement was used in a variety of ways by clients, contractors, sub-contractors and suppliers in the procurement process.

The report also concluded that the rise in the use of design and build procurement has encouraged the use of contractor’s bills of quantities where few documents are prepared to a standard format, say, for example, in accordance with SMM7. Further, it was alleged that SMM7 was out of date and represented a time when bills of quantities and tender documents were required to be measured in greater detail than is warranted by current procurement practice and therefore a new approach was required.

NRM2

NRM2 is much more than just a set of measurement rules and is divided into the following sections:

Part 1: General

NRM2 opens with a general section, that outlines the big picture of the RICS New rules of measurement suite and how NRM2 fits into the whole NRM project - that is estimating and cost planning through to built-asset management.

Part 2: Measurement rules for bill of quantities for work procurement

Part 1 is followed by a lengthy section describing the purpose and benefits of bills of quantities in rather a text book like approach. There is a section on risk and how bills of quantities should be codified and in addition there is a typical example of a structure for use when procurement is based on work packages instead of bills of quantities. In some ways this approach is similar to CESMM4.

Part 3: Tabulated rules of measurement for works procurement

This part of NRM2 begins by describing the protocols and use of the tabulated rules of measurement document. This section should be carefully studied as it contains information that applies across the trade sections.

The tables of information for the work sections are laid out over 6 columns and 3 levels and are used unless otherwise stated, as follows:

  • Column 1 describes the item or work to be measured;
  • Column 2 gives the unit in which the item or work is to be measured;
  • Column 3 lists the information, including critical sizes or dimensions that must be given in the bill description;
  • Column 4 lists supporting information that must be given in the bill descriptions;
  • Column 5 lists further supporting information including any additional dimensional requirements;
  • Column 6 (notes, comments and glossary) explains what work is deemed to be included in specific building components.

Each description will usually contain information from columns 1, 2 and 3 and as many items from columns 4 and 5 as are applicable to the item being measured and when relevant, information from column 6.

In addition because NRM2 has been drafted with the preparation of sub-contract packages in mind there are more work sections; 41 Sections in NRM2 compared with 22 Sections in SMM7. Another important difference is that NRM2 is available as a free download in PDF format for RICS members. Also the Preliminaries section of NRM2 is much more extensive than SMM7.

Note that in all cases the traditional measurement conventions, for example, calculating mean girths, are identical to SMM7. The status of the rules of measurement is the same as other RICS guidance.

A number of work sections in NRM2 allows the measurer alternative approaches to billing quantities, for example, section 11 In-situ concrete work, thereby giving the opportunity to incorporate quantities generated through BIM.

Civil Engineering Standard Method of Measurement (CESMM4)

Sponsored and published by the Institution of Civil Engineers the first edition of CESMM3 appeared in 1976 in order to 'standardise the layout and contents of Bills of Quantities and to provide a systematic structure'. The current, fourth edition, was published in 2012.

These 2 standard methods of measurement reflect the different approaches of the 2 industries, not only in the nature of the work, but also the degree of detail and the estimating conventions used by both sectors. This in turn reflects the different ways in which building and civil engineering projects are organised and carried out. In general the NRM2 has  more emphasis on detail, where as the CESMM4 takes a more inclusive approach to the measurement process. Building work comprises many different trades where as civil engineering works consists of large quantities of a comparatively small range of items. For example CESMM4 has no provision for the measurement of mechanical and electrical installations of basic building work. The principle difference between CESMM3 and 4 is that the current 4th edition is contract-neutral.

Other methods of measurement

Other methods of measurement are available for specific types of construction, most notably:

  • Standard method of measurement for highways;
  • Standard method of measurement for roads and bridges;
  • Standard method of measurement for industrial engineering construction, which provides measurement principles for the estimating, tendering, contract management and cost control aspects of industrial engineering construction; and
  • RICS International method of measurement.

The UK standard method of measurement of building works have been used as the basis for the preparation of methods of measurement that are used in Malaysia and Hong Kong. It is anticipated that NRM2 will be similarly adapted in due course.