Overview of BOCC Approach* * International Comparison of Cost for Construction Sector, Walsh and Sawhney (2004)

BOCC Approach

Concrete Footing Component

Concrete Slab Component

Roadway Component

BOCC Hierarchy

Components of Systems for Residential System Name System Explanation Site-work Construction components related to site preparation of a residential construction project Substructure Structural components and related work items below the ground surface that are part of a residential construction project. These components are load-bearing and transfer all the loads from the superstructure to the ground below Superstructure Structural components and related work items above the ground surface that are part of a residential construction project. These components are load-bearing and provide resistance to live and dead load on the building Exterior Shell/ Building Envelope Construction components that form the exterior shell of a residential construction project. They are non-load-bearing members that rest upon the superstructure of the building Interior Partitions All interior walls and opening in the building Interior and Exterior Finishes All construction components in place for the purpose of satisfying a cosmetic function, including for example paint or plaster. Mechanical and Plumbing All construction components related to providing climate control or water services such as heating and cooling systems, hot and cold water systems, fire fighting systems etc. Electrical All construction components related to distribution of alternating current and direct current including electrical fixtures for a residential construction project

Components of Systems for Non-residential System Name System Explanation Site-work Construction components related to site preparation of a non-residential construction project Substructure Structural components and related work items below the ground surface that are part of a non- residential construction project. These components are lo-bearing and transfer all the loads from the superstructure to the ground below Superstructure Structural components and related work items above the ground surface that are part of a non- residential construction project. These components are load-bearing and provide resistance of all types of live and dead load on the building Exterior Shell/ Building Envelope Construction components that form the exterior shell of a residential construction project. They are non-load-bearing members that rest upon the superstructure of the building Interior Partitions All interior walls and opening in the building Interior and Exterior Finishes All construction components in place for the purpose of satisfying a cosmetic function, including for example paint or plaster Mechanical and Plumbing All construction components related to providing climate control or water services such as heating and cooling systems, hot and cold water systems, fire fighting systems etc. Electrical All construction components related to distribution of alternating current and direct current including electrical fixtures for a non-residential construction project

Components of Systems for Civil Works System Name System Explanation Site-work Construction components related to site preparation of a civil engineering project including earthwork, earthmoving, and surface treatments such sidewalks and pavements Substructure Structural components and related work items below the ground surface that are part of a civil engineering project. These components are load-bearing and transfer all the loads from the superstructure to the ground below Superstructure Structural components and related work items above the ground surface that are part of a civil engineering project. These components are load-bearing and provide resistance to live and dead loads Mechanical Equipment Equipment installed on civil engineering projects such as pumps, turbines, boilers, air handling equipment, cooling towers, vessels etc including all connecting pipes and valves. Mechanical includes utility systems (steam, compressed air, and refrigeration), process systems (rotating pumps, compressors, agitators, filters, etc.) special vessel design (tanks, pressure vessels), etc. Electrical Equipment Equipment installed on civil engineering projects for power distribution systems, substations, power distribution panels, motor control centers, lighting, communications, etc. Underground Utility Any underground line, system or facility used for producing, storing, conveying, transmitting, or distributing communication or telecommunication, electricity, gas, petroleum and petroleum products, coal slurry, hazardous liquids, water under pressure, steam, or sanitary sewage. These include wires, ducts, fiber optic cable, conduits, pipes, sewers, and cables and their connected appurtenances installed beneath the surface of the ground

Construction Components Construction Component Residential BasketNon-Residential Basket Civil Engineering Works Basket Aggregate Aggregate Base Column Footing Culvert Drilled Shaft Earthwork Electrical Service Point Exterior Paint Exterior Wall Cement Plaster Interior Ceiling Plaster

Construction Components Construction Component Residential BasketNon-Residential Basket Civil Engineering Works Basket Interior Painting Interior Wall Plaster Portland Cement Reinforcing Steel Roadway Lane Round Bridge Pier Sand Sand Filter Structural Column Round Structural Column Square

Construction Components Construction Component Residential BasketNon-Residential Basket Civil Engineering Works Basket Round Bridge Pier Aluminum Frame Window Bridge T Beam Bridge Spread Footing Concrete Airfield Pavement Exterior Sidewalk Masonry Interior Wall Concrete Structural Steel Unskilled Labor

Construction Components Construction Component Residential BasketNon-Residential Basket Civil Engineering Works Basket Skilled Labor Backhoe Vibratory Plate Compactor Centrifugal Pump Plywood

Advantages of BOCC Approach The BOCC provides a much simpler and better defined price comparison tool. It drastically reduces the resource and expertise requirements in the price collection process. It underlines the importance of the various components comprising different sets of labor and materials as well as equipment use. It thus captures productivity differentials by accounting for labor and equipment trade-off. Allows reasonable flexibility to compare different construction projects by identifying core components that are common across countries. Many countries have shown interest and asked for technical support to adapted the BOCC approach for use as a national inter-temporal price comparison tool to build their capacity.

Labor Equipment Trade-off

Price Collection Process

Overview of Price Collection BOCC uses the SPD/PS methodology for price collection Identified components are representative and comparable Components are converted into SPDs for price collection purposes Country resources such as public works department and published schedule of rates can be used for pricing

Price Comparison Under BOCC In the BOCC method 34 Components are identified. They include: Two types of labor – skilled and unskilled. Four types of equipment for hire – a back-hoe, a centrifugal pump, a vibratory plate compactor and a sand filter. Five kinds of building material – Portland cement, sand, plywood, reinforcing steel, and aggregate. “Aggregate” is gravel which, together with cement, water and sand, is used too make concrete. Complete components including a mix of labor, equipment and material. Prices for the 34 components are used to obtain PPPs for Systems. PPPs for systems together with expenditure weights are then used to obtain PPPs for residential buildings, non-residential buildings, and civil engineering works.

Who collects the data? Building engineers, architects, quantity surveyors or other experts have to be involved Most statistical agencies do not have the necessary expertise Some countries may be able get the help of specialists from public works departments Other government agencies responsible for building regulations may also be useful In other countries the work has to be contracted out to construction firms or freelance engineers

When and where data are collected In principle the prices should be national annual average. This means data collection should be across regions and should cover all year (quarterly), but this would be excessively costly. In practice some simplifications are necessary for construction sector. Prices should only be collected in 2 or 3 three cities that would give a close approximation to national average. In smaller countries this may not be a major issue. In large countries the scope of coverage should be extended to cover major cities and regions. Price collection in mid-year is recommended.

How many observations? For building materials and for equipment multiple pricing is recommended Ideally, prices should be collected from at least four or five outlets again with the objective of providing an approximation of national average Again this may not be a major issue I relatively small countries with low price variations. In large countries the scope of coverage should be extended to cover major cities and regions For skilled and unskilled labor the number of observations required depends on the data sources used

What is in the cost estimate? For the completed components the price is the total of the cost, at purchaser prices of the materials, labor and equipment. The price reported for completed components does not include any profit margin or any fees for architects, quantity surveyors and other construction specialists The purchaser prices of the materials and hire of equipment includes only non-deductible product taxes. Value added taxes are often fully deductible for goods and services that are considered to be investments and so will usually be excluded from the purchaser price.

Expenditure Weights

Expenditure Weights in BOCC

Sample System Weight W2 Cost Breakdown for Construction in Canada for Year 2000 Systems Multi Level parking Garage Light IndustrialWarehouse Commercial Office Building Elementary School High rise office complex Substructure9.1%8.7%6.4%2.1%1.8%3.7% Structure58.3%21.2%18.9%16.2%11.5%20.1% Exterior Closure7.0%19.3%36.4%14.2%16.4%16.0% Partitions and Doors0.7%0.9%7.0%5.0%7.4%4.7% Finishes4.07.8%0.6%8.4%10.3%9.3% Fitting and Equipment2.8%5.6%0.0%5.3%8.8%9.6% Mechanical6.2%17.7%20.9%26.5%25.6%19.9% Electrical4.9%12.3%2.4%14.9%10.7%9.3% General Requirements and Fees7.0%6.5%7.4% Total100%