Quantification & Costing Flashcards
What is COMP6?
- Code of measuring practice, 6th edition.
- RICS published this guidance note in 2007 (updated in 2015 to apply globally).
- Provides definitions that permit the accurate and consistent measurement of buildings and land.
Are you aware of any other measurement standards?
IPMS – International Property Measurement Standards drafted by the IPMSC (committee). Standards establish a consistent methodology for measuring Industrial, Office, Residential and Retail buildings globally.
SMM7 – Standard Method of Measurement (SMM) published by RICS. Provides rules for measuring building works for preparing documents such as BQs. Superseded by NRM2.
(CESMM – Civil Engineering Standard Method of Measurement published by Institution of Civil Engineers (ICE). Sets out procedure for preparing BQs for civil engineering works.)
(POMI – Principles of Measurement (International) published by RICS. Guidance for measuring building works quantities for the BQs.)
What’s the difference between COMP6 and IPMS?
IPMS 1 vs GEA – e.g. IPMS1 includes balconies external to main structure (but stated separately).
IPMS 2 (Office) vs GIA – e.g. IPMS2 (Office) includes balconies external to main structure (but stated separately).
IPMS 3 (Office) vs NIA – e.g. IPMS 3 (Office) includes all internal walls and columns, as well as balconies (but these are stated separately)
Define GEA
Code of Measuring Practice, 6th edition says:
“Gross External Area is the area of a building measured externally at each floor level.”
EXCLUDES:
- Voids over or under structural floors.
(INCLUDES:
- Perimeter wall thickness and external projections
- Internal walls & partitions
- Columns, piers, chimney breasts, stairwells, lift-wells
- Internal balconies
- Areas with headroom <1.5m.
- Pavement vaults
EXCLUDES:
- External open-sided balconies, covered ways and fire escapes
- Canopies
- Voids over or under structural, raked or stepped floors)
Define GIA
COMP6 says:
“Gross Internal Area is the area of a building measured to the internal face of the perimeter walls at each floor level.”
EXCLUDES:
- Voids over or under structural floors.
(INCLUDES:
- Internal walls & partitions
- Columns, piers, chimney breasts, stairwells, lift-wells
- Internal open-sided balconies, walkways, and the like
- Areas with a headroom <1.5m
- Pavement vaults
EXCLUDES:
- Perimeter wall thicknesses and external projections
- External open-sided balconies, covered ways and fire escapes
- Canopies
- Voids over or under structural, raked or stepped floors)
Define NIA
COMP6 says:
“Net Internal Area is the usable area within a building measured to the internal face of the perimeter walls at each floor
level.”
EXCLUDES:
- Columns
- Areas with a headroom <1.5m
- Areas rendered substantially unusable due to having a dimension between opposite faces of <0.25m
- Non-usable areas such as plant rooms, circulation areas, cores etc
(INCLUDES:
- Non-structural walls subdiving accommodation in sole occupancy
- Pavement vaults
EXCLUDES:
- Stairwells, lift-wells and permanent lift lobbies
- Internal structural walls, walls enclosing excluded areas, columns, piers, chimney breasts etc);
What is NRM2?
New Rules of Measurement 2 - Detailed measurement for building works
Provides guidance on:
- quantifying and describing building works when preparing BoQs, schedules of works and schedules of rates.
What is the structure of NRM2?
- General Introduction
- Contextualises cost estimating in terms of RIBA Plan of work and OGC Gateway process
- Purpose
- Use
- Date effective - Detailed measurement of building works
- Information on BQs including: definition, purpose, benefits and types. - Rules of measurement for building works
- Tabulated rules for the measurement and description of building works.
- Work sections 1-41
- Item, UoM, Level 1-3 (description information reqs), Notes (clarifies approach to quantification).
- (Bulk of NRM2)
Appendices
- Guidance on preparing BoQs
- Templates for various pricing documents;
What are the key headings for contractor preliminaries identified in NRM2?
Employer’s requirements:
- site records
- completion and post-completion requirements
- site accommodation
MC’s cost items:
- site records
- completion and post-completion requirements
- management and staff
- mechanical plant
- temporary services
- insurance, bonds, guarantees and warranties
How would you measure MEP elements of a cost plan?
- Identify MEP elements in the design.
- Measure in accordance with NRM1 “4. Tabulated rules of measurement for elemental cost planning”
Group element 5: Services
- Element 5.1: Sanitary installations (for e.g.)
- Sub-element: 5.1.1 Sanitary appliances
- Component: 1 Sanitary appliances: details to be stated.
- Unit = nr
- Measurement rules for components: C1 Where components are to be enumerated, the number of components is to be stated.
- Included: WC pans and cisterns, urinals and cisterns.
- Excluded: Sanitary installations procured as part of a prefabricated building, building unit or pod.
(NRM1, p201)
How would you measure partitions for a cost plan?
- Measure in accordance with NRM1 “4. Tabulated rules of measurement for elemental cost planning”
Group element 2: Superstructure
- Element 2.7: Internal walls and partitions
- Sub-element: 2.7.1 Walls and partitions
- Component: 1 Internal walls: details, including thickness (mm), to be stated
- Unit = m2
- Measurement rules for components: C1 Measure area of partition, measured on the partition centre line. No deductions for door openings, screens etc
- Included: 1 Internal walls, including full-height and low-level walls
- Excluded: 1 Internal skin of external walls
(NRM1, p169)
What is BIM?
- Building Information Modelling.
- Using a shared digital representation of a building to facilitate design, construction and operation processes to form a reliable basis for decisions (ISO 19650).
(We use BIM Level 2 (Full collaboration): use of many 3D models which are federated. Level 3 (Full integration iBIM): one model in cloud environment which project team can access.)
(Government requires fully collaborative 3D BIM at Level 2 (with all project and asset information, documentation and data being electronic) as a minimum by 2016.)
(Autodesk A360, Revit, CostX, Bluebeam)
What are the advantages of BIM?
- TIME & ACCURACY: Harvesting quantities from the model is faster and more accurate, only takes 30% of the time –> beneficial for large take-offs.
- RISK: Providing contractors further clarity around the design and logistics - enables them to mitigate risk due to better coordination.
- COORDINATION: use Navisworks to create federated model and then run clash detection to ensure no collisions.
- PROCUREMENT: contractors want models, they promote interest in the project and help secure the project team.
- TRANSPARENCY: walk through design and ensure all elements of design are captured, increases understanding of project
(BIM smooths resourcing over the RIBA stages).
What are the disadvantages of BIM?
-COST: Software licences, training staff to use it
-LEGAL: New technology, limited case law in the area
-ATTITUDES: Project team members reluctance to use BIM.
Tell me about inputting data into BIM
COSTX:
- Loading in drawings: DWG (1:1 – no scaling required) > PDF > JPGs/PNGs
- CostX workbooks: input item descriptions, rates, formula to calculate the total cost
Tell me about extracting data from BIM
REVIT: QS agrees with client how the costs are going to be reported early in the project so that model can be set up accordingly. Most common and successful method to harvest quantities:
- ‘Tag’ elements to group them
- create schedule –> choose fields, adjust sorting, grouping, filtering –> export schedule
COSTX: measuring quantities into dimension groups using line or point tool
What is the CIC BIM protocol Second edition?
- Construction Industry Council Building Information Modelling protocol.
- UK’s only standard contractual BIM protocol.
- Legal agreement that can be incorporated into construction contracts
- Establishes specific obligations, liabilities and limitations on the use of building information models and defines deliverables to a specific level of detail (LOD) for ‘data drops’ at key stages during the development of the project.
- Suitable for use on all Level 2 BIM Projects.
What is a CSA?
- Contract Sum Analysis
- Document prepared by contractor as part of their tender on D&B projects, PQS can define the format.
- Breaks down contractor’s price, allowing client to analyse it and compare it to other tenders.
- Can be used as a basis for calculating payments due to the contractor as works progress.
- Necessary as unlikely to be BQ on a D&B project at the time the contract is entered into.
What is a schedule of rates?
- A list of construction activities with pre-agreed rates, which the contractor can place their quantities against.
- Typically used when the nature of work required is known but it cannot be quantified.
What is a schedule of works?
- A list of the work required, allows contractor to calculate the required quantities and identify significant work and materials needed to complete the works (risk of accuracy on the quantities lies with contractor)
- Typically used on smaller projects or for alteration work.
What is a bill of quantities (BoQ)?
NRM2 says:
- A list of items that gives detailed descriptions and firm quantities of the contract works.
- Primarily used for tendering.
At which RIBA stage are BoQs prepared?
RIBA Plan of Work Overview 2020 says:
- Typically RIBA Stage 4
When/why would you use a BoQ instead of a cost plan?
BQs:
- quicker to prepare than cost plans
- typically used for tendering
- good for competitive tendering, saves contractors time
- good for post-contract cost control e.g. valuing variations
