Latest trend in building construction is Design and Build projects. In conventional contracts, a consultant is appointed to design and the contractor is supposed to construct following the design. In Design and Build projects, the consultant prepares a concept report and the contractor is supposed to design and construct following the guidelines mentioned in the report.
There are several advantages to both parties in Design and build projects. As several contractors participate in the tender, all of them do their homework. This produces several value engineered versions of the project. Each and every contractor try to get the job. In this process they optimize the systems. Client can choose best option at the lowest possible price. More flexibility to both client and contractor is another advantage.
In Design and Build projects, normally MEP design is fully carried out by the MEP contractor.
There are several sub-contractors in this process including but not limited to the following
Electrical Contractor for Electrical power, lighting, ELV, Fire Alarm, Emergency Lighting etc.
AC contractor for HVAC works
Plumbing Contractor for Water supply and Firefighting systems
MEP Contractor scope of work is as follows:
- Prepare a detailed concept report following client’s concept report and Authority Guidelines.
MEP contractor shall carry out necessary value engineering at this stage. The contractor needs to focus on client’s objectives and authority guidelines including regulations of DEWA, Civil Defense, DM. Etisalat/Du etc. At this stage, contractor should impress the client by providing a design meeting his expectations
- Schematic Design showing the locations of all devices and equipment
Detailed calculations are not required at this stage. Locations of equipment and devices including lighting fixtures, socket outlets, panels, HVAC equipment, Water supply systems, Firefighting equipment etc, are required. A typical apartment/office/guest room layout needs to be provided for the client to review and decide.
- Detailed Design
Calculations for electrical and mechanical systems need to be produced at this stage. Minimum Calculations are as follows:
Lux level calculations using Dialux or similar software to design lighting
Load schedules
Generator Sizing
Voltage drop
HVAC calculations in HAP
Water supply calculations
Firefighting calculations
- Shop Drawings
Shop drawings will have similar drawings of detailed design but with dimensions and details.
- Material and shop Drawings Submission and approval.
Approval by client and authorities shall be obtained prior to placing of material orders and commencement of construction.
- Procurement
The MEP contractor shall place order for all required materials and systems and ensure that the systems are delivered in line with the project program. Necessary subcontractors and specialist contractors need to be finalized and contract needs to be signed.
- Construction of MEP systems
Construction of MEP systems requires a lot of coordination with other services. Construction involves following phases
First fix- This is usually embedded conduits and sleeves in slabs and columns
Second Fix-Cable trays, Ducts, conduits in walls, DB enclosures etc.
Final Fix- Cabling, Busbars, Panels, HVAC equipment, Lighting, Water supply equipment. Sanitary wares etc.
Testing and Commissioning
Authority Inspection
- As Built Documentation
As built drawings, material data sheets and operation and maintenance manuals shall be submitted after completion of the project.