| Name : |
Identifer(s) : |
TypeTask : |
Definition : |
| Perform Mechanical, Electrical and Piping Quantity Take Off |
MEP_QTO
|
process_model |
This process map document is about determining quantities of materials used, or expected to be used, in mechanical electrical and plumbing (public health) or MEP engineering installations. The determination of quantities is undertaken progressively throughout the design and construction of a project and makes use of the information that is available at the time. It starts at the earliest stage when information may be available only about the type of building required together with its expected overall size and location. As more detail is added to the design, quantity measurement can be refined based on area measurement of spaces until estimates can be developed based on complete knowledge of the elements to be incorporated within the project.
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| Perform Feasibility Design |
P_FD
|
process_model |
At feasibility, design information may be available only as a series of requirements that indicate the intended purpose, size and content of the building. It may be possible through the requirements of the building to establish areas to be serviced, types of services to be provided and possibly, for some key entities, approximate numbers expected,
Feasibility design is a collapsed sub-process that combines the outline and substantive feasibility design stages.
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| Perform Outline Feasibility |
P_OF
|
process_model |
Perform Outline Feasibility
|
| Perform Substantive Feasibility |
P_SF
|
process_model |
Perform Substantive Feasibility
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| Perform Outline conceptual design |
P_OCD
|
process_model |
At outline conceptual design, it is expected that spaces within the building will have been laid out so that area information is available down to the level of the individual space. This should also include all circulation spaces. It is also expected that all spaces will have been identified in terms of their name and purpose according to whatever naming conventions/classifications are in place for this. It is also expected that all requirements will have been provided so that key distribution elements within spaces are identified. The provision of requirements information should be enough to assess numbers of items in a space and to allow an estimate of overall loadings to be made so that size of major plant can be assessed.
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| Perform Full conceptual design |
P_FCD
|
process_model |
At full conceptual design, it is expected that all of the systems will have been designed and that initial modelling will have been done. This includes the sizing of systems so that the MEP quantity surveyor can determine how much of each size of flow segment is required.
From an MEP perspective, it is at this stage that there should be sufficient information available to enable quantities to be assessed in terms of the systematic provision (i.e. by counting what is there) rather than their spatial performance.
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| Perform Coordinated design and procurement |
P_CDP
|
process_model |
All systems will be fully designed, detailed and modelled for coordinated design. The only thing that may be missing from the design is the precise manufacturer specification of some
components, particularly if the the installation / construction work is to be determined by a contractors final decision.
Coordinated design includes all other specified requirements including both quality and performance. The MEP quantity surveyor can, depending on what information is considered necessary, determine both actual and measured lengths of flow segments, their coverings and builders work requirements, together with all fitting, fixing, carrying and waste provisions.
Coordinated design should enable the MEP quantity surveyor and designers to obtain quantity information necessary for tendering and procurement, scheduling, delivery and prefabrication, asset management, maintenance and other purposes.
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| Reiterate Feasibillty Design |
R_FD
|
reiteration |
Reiterate to start
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| Reiterate Outline Feasibility |
R_OF
|
reiteration |
Reiterate to accept feasibilty design
|
| Reiterate Substantive Feasibility |
R_SF
|
reiteration |
Reiterate to accept outline design
|
| Reiterate Outline conceptual design |
R_OCD
|
reiteration |
Reiterate to accept feasibilty design
|
| Reiterate to Full conceptual design |
R_FCD
|
process_model |
Reiterate to accept outline design
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| Reiterate to Coordinated design and procurement |
R_CDP
|
reiteration |
Reiterate to accept full design
|
| Estimate MEP order of magnitude costs |
MEP_CST_OOMQ
|
information_requirement |
Estimate Mechanical, Electrical and Piping order of magnitude costs
|
| Estimate MEP preliminary costs |
MEP_CST_PQ
|
information_requirement |
Estimate Mechanical, Electrical and Piping preliminary costs
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| Eastimate MEP approximate costs |
MEP_CST_AQ
|
information_requirement |
Estimate Mechanical, Electrical and Piping approximate costs
|
| Estimate MEP pre construction costs |
MEP_CST_PCQ
|
information_requirement |
Estimate Mechanical, Electrical and Piping pre construction costs. Note that specific pre-construction estimates may be required for particular element groupings either as sections of a whole estimate or as separate estimates. For example, the distribution elements forming the building services system may be within a different pre-construction estimate to the building and structural elements.
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| Exchange MEP order of magnitude quantities |
ER_MEP_QTO_OOMQ
|
exchange_requirement |
For feasibility, it is expected that area quantities will be the primary information available and that this will be in terms of major functional areas and possibly spaces if requirements (through briefing space programming) are already established. This information is relevant for downstream cost calculations that will most probably use historical information.
The method of measurement for the quantities should be determined. At this stage, it is unlikely to be a rule based method but based on a general measurement of the building / building story shapes. In the absence of an industry standard classification, it is probable that an organization specific classification will be used. Building information in terms of its purpose/use group should be classified. Building information should include whether it is a new project or a refurbishment. Major items of plant and equipment may be identified (either specifically or in general terms) and some indication of the performace of such items established. Quantities are determined from expected major cost breakdowns for the project or, if this is not available, by the primary system types expected to be included within the project.
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| Exchange MEP preliminary_quantities |
ER_MEP_QTO_PQ
|
exchange_requirement |
Preliminary quantities determined will be based on the type of element being considered. For some elements, quantities may be assessed by area (for instance, expected number of light fittings per square meter in office spaces). However, quantities for other elements may be based on counting the number expected. The precise method of quantification at this stage is entirely dependent on the way in which historical data is recorded and maintained (whether this is through a public service or whether it is recorded and maintained by a company locally).
The method of measurement for the quantities should be determined. At this stage, it may be a rule based method for areas but there are unlikely to be specific measurement rules for counting objects.
Classification systems should be selected for classifying elements. This includes both the spaces used for area quantification and the elements that are counted. This is relevant for later quantity breakdowns which may be at a further level of decomposition of the information at outline conceptual design.
For pipework and ductwork, the number of 'terminals' that may be located on a system may be used with appropriate factors. For some systems these may be flow terminals; for other systems, the terminal may be a different entity (e.g. a waste outlet or a sanitary element). Where rules/factors can be established that relate a number of units to a length of flow segment, then linear quantities can be established. Rules/factors should be varied according to building type, density of servicing, building usage, overall building shape, number of vertical risers and more.
For electrical systems, using numbers of switches and loads and then allowing a cable length per switch or load can deliver quantities. From this, an expected value of cable carriers (conduit, tray, trunking, ladder) can be assessed.
With linear values established, initial assessments can also be made of delivery quantities and a view taken on the logistics of delivery to site and required storage space. For ductwork and pipework, this may also include making assessments of delivery weights.
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| Exchange MEP approximate quantities |
ER_MEP_QTO_AQ
|
exchange_requirement |
This exchange requirement assumes that a full conceptual building model has been defined and that relevant information can be obtained from shape representations that it contains. The full conceptual model provides sufficient detail to enable the extraction of information to enable the approximate quantities to be derived. For instance, in defining a system group for a heating system, the group should contain all of the heat emitters within the system
Approximate quantities determined will be based on a model of the systems layout. Since the model is expected to include lengths, sizes and elevations of the flow elements, it is expected that all quantities from this stage onwards are based on a measure of actual elements and not by a historical performance criterion.
It is not necessarily expected however that systems will be fully detailed at this stage. Smaller elements and additions to systems such as air vents, drains, measuring points and instrumentation etc. are likely to be not yet included.
The method of measurement for the quantities should be determined. This will include determining the approach to be used for determining the overall length of flow segments used (pipework, cable or ductiing and how to estimate fittings used.
Classifcation systems should be selected for classifying elements. This includes both the spaces used for area quantification and the elements that are counted. This is relevant for later quantity breakdowns which may be at a further level of decomposition of the information at outline conceptual design.
Pipework should be set out so that quantities of flow segments at different elevations (below floor, low level, high level and above ceiling) can be found. Once this is established, the following additional quantities can also be determined.
- By considering the configuration of systems (complexity, density etc.), an allowance of additional length quantity of pipework could be made so that it is not necessary to actually count how many of each type of fitting is required
- The total number of fittings may be counted but rather than counting each individual type, they may be expressed in terms of a 'counted fitting' (the term used to identify the idea of a hybrid fitting consisting of j% elbow, k% tee, m% union, n% bend may vary between places)
- Counted fittings could be quantified at this stage as being some number per 100m of pipework (e.g. 30 counted fittings per 100m). This is an alternative to adding a length but may be easier than doing an actual fitting count. It has the advantage that it preserves the idea of fittings within a quantity set.
- Allowances can be made for fixing (hangers and brackets). Typically however, fixing allowances are made when costing. It could be done by making a length allowance to the pipework but this might later distort any quantity take off used for ordering purposes.
- Weight quantities can be assessed either by system or overall.
- Because pipe sizes, lengths and elevations are known, labor estimates could also be made in terms of time quantities so that an overall assessment of labour requirement can be made. This is valuable since it facilitates the assessment of local labor availability and/or potential travelling requirements
For ductwork. schedules of flow segments can be determined by length. Flow segments of particular sizes use particular thicknesses of materials in their manufacture and this can give an idea of overall weight. This is relevant since, at this stage, it is common for ductwork costing to be assessed by the weight of material used.
For electrical installations, it is expected at this stage that main distribution cables between distribution boards should be able to be determined by length. However, cabling for final circuits is probably still based on a length assessment by counting runouts to switches, outlets and final loads and then allowing an expected length per runout. However, it is expected that lengths of conduit, tray, trunking, ladder should be able to be assessed in the same way as for pipework and ducting.
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| Exchange MEP pre construction quantities |
ER_MEP_QTO_PCQ
|
exchange_requirement |
his exchange requirement assumes that a full conceptual building model has been defined and that relevant information can be obtained from shape representations that it contains. The full conceptual model provides sufficient detail to enable the extraction of information to enable the pre-construction quantities to be derived.
Note that the general principles of defining a pre-construction estimate are similar to those for defining an approximate estimate. The difference between the exchange requirements is that the cost value information associated within a pre-construction estimate is expected to be better defined than for an approximate estimate so that it can be used as an indicator of expected construction cost.
Preconstruction quantities determined will be based on a detailed model of the systems layout. The model will enable capture of nominal lengths of flow elements as well as their sizes and elevations. From this, more detailed quantities of insulation and other coverings as well as detailed information about fixings can be obtained. More detailed lengths of flow elements (particularly for pipework and ductwork) could also be obtained to support a highly detailed cutting list for prefabrication of components if necessary.
Systems are expected to be fully detailed at this point with all of the information necessary for quantity takeoff as determined by the method of measurement selected. Note that this does not necessarily mean that every last detailed needs to be included in the model since measurement rules are expected to capture the precise detail.
Note also that, particularly for electrical systems, coordinated design may define the provision of carrying equipment and identify services to be carried, but it is unlikely that the precise routing of all electrical systems will be shown. This is especially true of final circuits which may be defined with 'logical lengths', the extent of which have to be determined in much the same way as was the case for preliminary quantities.
The method of measurement for the quantities should be determined. This will include determining the approach to be used for determining the overall length of flow segments used (pipework, cable or ducting) and how to estimate fittings used.
Classification and naming systems should be selected for identifying elements and their properties. This should include not only the level of detail for components using national classification systems but also the common specification of properties according to a standard dictionary.
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| RelSequence : |
Prior : |
Subsequent : |
Definition : |
| finish_start |
MEP_QTO_BEG
|
MEP_QTO
|
On completion of : Start MEP QTO
Commence : Perform Mechanical, Electrical and Piping Quantity Take Off
|
| finish_start |
MEP_QTO
|
MEP_QTO_END
|
On completion of : Perform Mechanical, Electrical and Piping Quantity Take Off
Commence : Terminate Design
|
| finish_start |
MEP_QTO_BEG
|
P_FD
|
On completion of : Start MEP QTO
Commence : Perform Feasibility Design
|
| finish_start |
P_FD
|
MEP_QTO_AFD
|
On completion of : Perform Feasibility Design
Commence : Accept Feasibility Design
|
| finish_start |
MEP_QTO_AFD
|
P_OCD
|
On completion of : Accept Feasibility Design
Commence : Perform Outline conceptual design
|
| finish_start |
P_OCD
|
MEP_QTO_AOCD
|
On completion of : Perform Outline conceptual design
Commence : Accept Outline Conceptual Design
|
| finish_start |
MEP_QTO_AOCD
|
P_FCD
|
On completion of : Accept Outline Conceptual Design
Commence : Perform Full conceptual design
|
| finish_start |
P_FCD
|
MEP_QTO_AFUD
|
On completion of : Perform Full conceptual design
Commence : Accept Full Design
|
| finish_start |
MEP_QTO_AFUD
|
P_CDP
|
On completion of : Accept Full Design
Commence : Perform Coordinated design and procurement
|
| finish_start |
P_CDP
|
MEP_QTO_ACD
|
On completion of : Perform Coordinated design and procurement
Commence : Accept Coordinated Design
|
| finish_start |
MEP_QTO_ACD
|
MEP_QTO_END
|
On completion of : Accept Coordinated Design
Commence : Terminate Design
|
| finish_start |
MEP_QTO_AFD
|
R_FD
|
On completion of : Accept Feasibility Design
Commence : Reiterate Feasibillty Design
|
| finish_start |
MEP_QTO_AOCD
|
R_OCD
|
On completion of : Accept Outline Conceptual Design
Commence : Reiterate Outline conceptual design
|
| finish_start |
MEP_QTO_AFUD
|
R_FCD
|
On completion of : Accept Full Design
Commence : Reiterate to Full conceptual design
|
| finish_start |
MEP_QTO_ACD
|
R_CDP
|
On completion of : Accept Coordinated Design
Commence : Reiterate to Coordinated design and procurement
|
| finish_start |
R_FD
|
MEP_QTO_BEG
|
On completion of : Reiterate Feasibillty Design
Commence : Start MEP QTO
|
| finish_start |
R_OCD
|
MEP_QTO_AFD
|
On completion of : Reiterate Outline conceptual design
Commence : Accept Feasibility Design
|
| finish_start |
R_FCD
|
MEP_QTO_AOCD
|
On completion of : Reiterate to Full conceptual design
Commence : Accept Outline Conceptual Design
|
| finish_start |
R_CDP
|
MEP_QTO_AFUD
|
On completion of : Reiterate to Coordinated design and procurement
Commence : Accept Full Design
|
| finish_start |
P_FD
|
ER_MEP_QTO_OOMQ
|
On completion of : Perform Feasibility Design
Commence : Exchange MEP order of magnitude quantities
|
| finish_start |
P_OCD
|
ER_MEP_QTO_PQ
|
On completion of : Perform Outline conceptual design
Commence : Exchange MEP preliminary_quantities
|
| finish_start |
P_FCD
|
ER_MEP_QTO_AQ
|
On completion of : Perform Full conceptual design
Commence : Exchange MEP approximate quantities
|
| finish_start |
P_CDP
|
ER_MEP_QTO_PCQ
|
On completion of : Perform Coordinated design and procurement
Commence : Exchange MEP pre construction quantities
|
| finish_start |
ER_MEP_QTO_OOMQ
|
MEP_CST_OOMQ
|
On completion of : Exchange MEP order of magnitude quantities
Commence : Estimate MEP order of magnitude costs
|
| finish_start |
ER_MEP_QTO_PQ
|
MEP_CST_PQ
|
On completion of : Exchange MEP preliminary_quantities
Commence : Estimate MEP preliminary costs
|
| finish_start |
ER_MEP_QTO_AQ
|
MEP_CST_AQ
|
On completion of : Exchange MEP approximate quantities
Commence : Eastimate MEP approximate costs
|
| finish_start |
ER_MEP_QTO_PCQ
|
MEP_CST_PCQ
|
On completion of : Exchange MEP pre construction quantities
Commence : Estimate MEP pre construction costs
|