Estimating Power & HVAC
Take off tips for Power & HVAC
There is no substitute for good preparation before you start an electrical estimating take-off. This careful preparation will pay off when it comes time to enter project information into your estimating software and later in the accuracy of your proposal. Before starting, take a few minutes to prepare your blueprints. On the top of your take off form, show the plan sheet number, floor number, area number or room number that you are taking off. This will help keep a record of where you found the various items.
Mark to remember - Mark the outlets you have counted with a colored pencil or highlighter. By marking everything as you go you can quickly scan the plan when you are done and see any outlets or other items that are not marked. If they aren’t marked, you probably didn’t count them.
Label the outlets with quality level and plate type. Be sure that you follow what the specifications say about using the proper outlet and mark floors, walls and ceilings with notation of type of construction.
Set up your take off sheet for outlet box types, such as frame, block or concrete boxes. Take all like and kind outlets off in a group, for instance power j-boxes, receptacles of one type, floor boxes and special outlets.
Tip - Use a thumb click (Tally) counter when counting outlets. This will allow you to keep track of your count if someone interrupts you or if you get a phone call.
Take off power outlets - Some Electrical Engineers will put a note on the plan that any receptacle adjacent to water sinks, are GFI type, but won’t show the GFI receptacles on the floor plan. Be careful of this! You will need to look close at the electrical and plumbing plans to spot and mark the GFI receptacles.
Some Engineers will use a GFI circuit breaker on circuits serving several receptacles adjacent to water sinks. Check the branch circuit design. You may have to provide an extra circuit conductor for the GFI protected circuits.
Look for isolated ground receptacles - If isolated ground receptacles are specified, check the branch circuit to verify that an isolated ground wire is shown. Check the panel schedule for isolated ground buss. Check the panel feeder for isolated ground wire.
If isolated ground receptacles are required and the isolated ground buss is not shown, send an RFI (request for information) to your customer. Ground wires and isolated ground busses will be required and can be expensive. Don’t leave them out!
The RFI will alert the other bidders to this so they will (hopefully) include the work in their prices as well. If RFI’s go unanswered or are vague, qualify your proposal that you have or don’t have the item in question included.
Floor boxes - Check the specification and description carefully on floor boxes. There are many configurations of floor boxes and the specifications are often not correct or incomplete.
Check floor construction (concrete slab, concrete over steel deck, wood or post-tensioned concrete). The floor construction will often determine which floor box type is correct. Look for the receptacle configuration (duplex, double duplex or power feed only) this will determine the proper top cover.
Check the data communication-cabling requirement for floor boxes to determine the proper type of top or data jacks. If this information is not available carefully qualify your proposal with what you have included.
When upper level floor outlets are the “poke through” type, include a core drill of appropriate size in your estimate for each outlet. If the floor is a post-tensioned slab, you may have to include an X-ray cost before core drilling.
Tip - You may need to include off hour or overtime allowances for floor boxes installed in upper levels over existing occupancy below.
Take off HVAC (Heating/Air Conditioning) connections - List all items of HVAC equipment on your take off sheet, such as: A/C units, VAV units, CU units, Air handlers, exhaust fans, chillers, pumps, cooling towers, etc.
List the item followed by a conduit and wire connection size and indicate indoor or outdoor (i.e. A/C #1, N1 (indoor) or N3R (outdoor) 1” w/ 3-6 & 1-10).
List the tonnage, HP or KW rating of the unit. Note any additional labor and material for items furnished with the unit such as separate variable frequency drive or other control package.
List disconnect switches (EXO's), motor starters and other control item on a separate take off sheet. Group these items as like and kind together for easier input to estimating program. Include disconnect switches: EXO 30 Amp 3 pole fused or non- fused, N3R or N1.
Magnetic starter, size X with accessories such as HOA, overload heaters, press to test pilot light, start-stop pushbutton. List fusible or non-fusible switch or circuit breaker. List N1, N3R N4, etc.
List any structural strut supports or fabricated iron supports.
Check mechanical control diagrams for any additional controls, conduit and wire to be furnished by electrical Div 16.
Plumbing connections (boilers, pumps, hot water heaters, etc.) - List items of plumbing equipment on your take off sheet.
Example: Boilers, boiler pumps, electric water heaters, hot water pumps, sump pumps, , sewage ejector pumps, fire pumps, booster pumps, fuel tanks and pumps, auto flush fixture controls, etc.
List the item followed by a conduit and wire connection size and indicate indoor or outdoor (WP Weather Proof)
Example: Cold water pump #1, N1 (indoor) or N3R (outdoor) 1” w/ 3-6 & 1-10. List HP or KW rating of the unit.
List any additional labor and material for items furnished with the unit such as separate variable frequency drive or other control package.
List EXO disconnect switches, motor starters and other control item on a separate take off sheet. Group these items as like and kind together for easier input to computer.
Example: EXO 30 Amp 3 pole fused or non fused, N3R or N1.
Magnetic starter, size X with accessories such as HOA, overload heaters, press to test pilot light, start-stop pushbutton.
List fusible or non fusible switch or circuit breaker. List N1, N3R N4 etc. Look for any structural strut supports or fabricated iron supports that may be required.
Check mechanical control diagrams for any additional controls, conduit and wire to be furnished by electrical Div 16. Check plumbing control diagrams for any additional controls, conduit and wire to be furnished by electrical Div 16.
Other equipment connections - Take off any other equipment that requires electrical connections such as kitchen equipment, irrigation equipment, parking control equipment signs, furniture systems etc.
List the item followed by a conduit and wire connection size and indicate indoor or outdoor. (WP)
Example: Cold water pump #1, N1 (indoor) or N3R (outdoor) 1”(conduit) w/ 3-#6 & 1-#10g.
List Horsepower or KW rating of the unit. List any additional labor and material for items furnished with the unit such as separate variable frequency drive (VFD) or other controllers.
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