Holding to Specifications: The HVAC Engineer's Responsibility

Holding to Specifications: The HVAC Engineer's Responsibility

When reviewing submittals, the engineer’s job is to determine whether the submitted product meets the specified requirements.

Contractors frequently ask engineers to approve submittals for equipment differing from the equipment in the engineers’ bases of design. In some of these cases, the contractor views the plans and specifications as “guides” permitting design modifications as part of the submittal-review process, while in others, the contractor genuinely wants to implement the design as specified, but prefers to use a different make of equipment because of cost, familiarity, and/or personal relationship with the vendor. Regardless, contractors often enlist vendors or manufacturers in efforts to persuade engineers to approve submittals.

During the design phase of a project, an engineer considers, compares, and evaluates products in the preparation of bid documents. The bid documents become the technical section of the construction contract. Then, the engineer’s job changes from that of designer to contract administrator.

Once bid documents are formalized, the question ceases to be whether the specified product features are necessary or even a good idea. The specified features are required, whether or not they are perceived as needed. When reviewing submittals, the engineer’s job is not to ask whether the submitted product is a good way to do the job or has advantageous features. The engineer’s job is to determine whether the submitted product meets the specified requirements. Two examples help to illustrate this principle.

Example 1: Centrifugal Chiller

An engineer based the specification for a centrifugal chiller on Manufacturer A’s offering. The engineer forwarded the draft documents to Manufacturer B for a competing selection. B also was supposed to review the draft specification and indicate whether the engineer inadvertently included features unique to A’s product. When the bids came in, B’s chiller was found to offer equivalent performance at substantially lower cost. The contractor, owner, and engineer all agreed B’s chiller was the better choice for the project.

When the engineer received B’s submittal, he did not see how B would provide some of the data points specified to appear on the chiller control panel. When asked about the missing points, B’s technical staff confirmed B’s control panel did not display that data, saying B’s technology made the data unnecessary. B missed the point. Whether or not the data were necessary to operate the chiller, they were specified; therefore, they were necessary to comply with the contract.

The engineer did not intend to make the specification proprietary to A. B should have reviewed the specification more carefully during design, when the engineer easily could have revised the specification to eliminate the problem requirements. But that opportunity was gone. The only question was whether B’s chiller met the specified contract requirements.

The engineer told B’s representative and technical staff the specification was a contract that B had to meet if it wanted to supply the chiller for the job. The engineer explained B could meet the contract by showing how the missing data could be derived from information displayed on B’s control panel. The engineer also explained B could meet the contract by demonstrating its technology was different from A’s, but functionally equivalent (making it a substitution), so there was no need to be able to read data relating only to the way A controlled its chiller.

Without question, the process would have been much smoother had the specification contained only requirements both A and B could meet. B was supposed to show how its product met the specified requirements or a functional equivalent, not that the specified requirements were foolish.

Example 2: Vacuum Condensate-Return System

A hotel asked an engineer to design a replacement vacuum steam-condensate-return system. After researching sizing guidelines and available product technologies, the engineer selected a liquid-ring-seal vacuum pump. He located a vendor who could fabricate and supply the built-up system. The specifications, however, allowed contractors to submit equivalent products from other manufacturers.

The selected contractor submitted a product from a vendor he knew and liked. That vendor’s standard product line did not include a system that met the specifications. The vendor tried to convince the engineer that the specified capacity was more than the job required and that his smaller system would be adequate. The vendor also tried to convince the engineer that a liquid-ring-seal-type vacuum producer was not necessary and that a competing technology would be a good solution for the project.

The design phase of the project was long over, the engineer explained. The contract and, therefore, job requirement was 200 cfm of vacuum-producing capacity. The engineer did not have the authority to accept the proposed 150-cfm vacuum pump. The engineer also explained he had considered other technologies, but concluded the ruggedness and durability of the liquid-ring-seal technology justified specifying it for this 24-hr-a-day/seven-days-a-week application. Therefore, the vendor had to supply a liquid-ring-seal pump, if he wanted to supply the equipment for this job.

The irony of the situation is the engineer had approached the vendor early in the design phase of the project. The vendor’s technical staff reported the manufacturer could not meet the job requirements. Strange that the manufacturer did not have enough faith in his product to provide data the engineer could use as the basis of design, but thought it was a “good enough” response to the bid documents.

Once the vendor understood the engineer was not going to use the submittal-review process to change the design criteria, he managed to submit a compliant product.

Closing Thoughts

If a manufacturer wants an engineer to approve its product as “equal,” the manufacturer’s job changes from selling the product on the basis of differentiating features to showing how the product performs the same functions as the basis-of-design product, but perhaps in a different way.

Vendors and representatives need to understand that their job during the bid phase of a project is to quote to the plans and specifications. If they have a question about the job or its requirements, they should contact the engineer before providing a price quotation to the contractor.

Asking an engineer to approve a submittal for a product that does not meet every aspect of a specification puts the engineer in an awkward position, as the engineer has a duty to interpret and apply design/contract documents impartially. Submittal review is not a chance to revisit design decisions. Just as a contractor would not allow an engineer to use submittal review to change the design and add features not specified in the contract documents, contractors and vendors should not expect engineers to use submittal review to change design criteria by waiving features specified in the contract documents.


A longtime member of HPAC Engineering’s Editorial Advisory Board, Kenneth M. Elovitz is an engineer and the in-house counsel for Energy Economics Inc. His knowledge of and experience with HVAC, electrical, and life-safety systems allows him to understand system function and performance, including interactions among disciplines. He is an adjunct instructor in the Architectural Engineering program at Worcester Polytechnic Institute.


Did you find this article useful? Send comments and suggestions to Executive Editor Scott Arnold at [email protected].

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