ASHRAE Journal - December 2019 - 56

COLUMN ENGINEER'S NOTEBOOK

owner's representatives. On a d/b job, contractors would
also participate. The selection is made by subjectively
and objectively weighing the pros and cons of each option, sometimes supported by more detailed energy cost
calculations. (See Example 1 and Example 2 below.)
8. Enter the final selection into equipment schedules and plans. The equipment can be fully coordinated
with other elements of the design following the manufacturer's installation instructions without concern that
a later substitution will be made.
9. (This step is only required for p&s projects.) "Flat
spec" the final selection with language to make it clear
that no additional proposals will be considered when the
project is released for general contractor bidding. For
example:
a. List the manufacturer and full model number in
the equipment schedule with "NO EQUAL" listed in the
Remarks column.
b. Include the equipment tag and price in the
equipment specification used for the CD bid, at the very
beginning of Part 1. For example:
A. Provide the scheduled chillers including the
scheduled options for the following price:
1. CH-1: $101,406
2. CH-2 and CH-3: $189,450 each
3. Price includes freight, but does not include
taxes.
B. Bids for other chillers will not be accepted.
c. In lieu of the Part 2 Materials Section, include a
detailed submittal of the selected equipment. This will
allow the contractor to coordinate rigging and other
installation details. This is particularly important for
products that ship in multiple sections, such as large
custom air handlers.

Post-Design Selection
Sometimes, it is not possible to bid and select equipment prior to bidding the rest of the mechanical work.
For example:
* Public projects may have bidding rules that do not
allow the design team to bid equipment.
* Some private owners also do not allow designers to
bid equipment because they do not believe the pricing
will be competitive. (This is a valid concern and discussed above; as noted, the equipment reps must understand they will be given only one chance to bid.)
* In some cases, especially on public projects, the
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D E C E M B E R 2 0 19

quality and other characteristics of contractors bidding
the project can vary such that reps are unwilling to use
the same pricing for all bidders, so firm pricing cannot
be obtained until the contractor is known.
* D/b projects are often bid very early in the design
process, e.g., after Schematic Design, when the HVAC
system design and equipment sizes are not known well
enough to get firm equipment bids.
Fortunately, it is still possible to use the procedure
above with a few tweaks:
1. Decide which equipment will be bid using this approach.
2. Obtain budget prices for each piece of equipment.
Typically, the equipment that is the basis of design
would be priced. It is not very important to get precise
pricing since the contract amount will be adjusted once
final selections are made.
3. Do not include the manufacturer and model numbers in equipment schedules so it is clear final selections
have not been made.
4. Stipulate the price in specifications as described in
Step 9 of the Design Phase Selection procedure above.
Make it clear that this price must be used in contractor
bids. Also request the percentage markup the contractor
applies to this equipment.
5. After the contractors are on board, bid and select
equipment as described in Steps 2 to 7 of the Design
Phase Selection procedure above.
6. Modify the design, if necessary, to accommodate
the final equipment selection. (The possibility of design
revisions is the main disadvantage of post-design bidding.)
7. Adjust the mechanical contract price by subtracting
out the stipulated equipment price and adding in the
final price, adjusted by the contractor markup.

Example 1: Chiller Selection
Large chillers are the most difficult pieces of equipment to select because they are custom products with
hundreds of selection permutations, so there are many
variables to consider. The rigorous life-cycle cost based
approach to chiller selection outlined in ASHRAE's CHW
plant design manual1 is best if the design schedule (and
fee) allow, but it is time consuming for both the design
engineer and chiller sales reps. This design manual also
outlines a Simplified Procurement Procedure that aligns
with the procedure described above. It is recommended

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ASHRAE Journal - December 2019

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