Comprehensive and Detailed Explanation From Exact Extract (CSI-aligned, paraphrased)

CSI emphasizes fairness, clarity, and equal information for all bidders. When controlled substitutions are permitted during bidding, the procedure typically described in Division 01 and the Instructions to Bidders is:

A bidder or manufacturer may propose a substitution for a specified product within a defined time before bid date.

The architect/engineer reviews the proposed substitution and may accept or reject it.

If the substitution is accepted, it must be communicated to all prospective bidders in a formal way so that every bidder is pricing the same requirements.

The correct formal mechanism during the bid period for changing procurement documents is an addendum. Therefore:

A substitution may be approved during bidding only if its approval is issued by an addendum to all bidders.

This maintains a level playing field and prevents one bidder from having a private advantage or a different scope basis than others.

Why the other options are not sufficient or correct alone:

B. The proposer of the substitution is notified in writingNotifying only the proposer does not put all bidders on the same basis. CSI stresses that changes affecting price, scope, or products must be distributed to all bidders via addenda during the procurement phase.

C. The architect/engineer accepts the substitution during the pre-bid meetingEven if verbally accepted in a pre-bid meeting, it must be officially documented by an addendum. Pre-bid meeting minutes alone are not a proper modification of the procurement documents unless they are explicitly issued as part of an addendum.

D. Specifications are revised and reissued to include the substitutionCompletely revising and reissuing specifications is not the usual or efficient method during a normal bid period. Instead, CSI practice is to use addenda to modify the existing specifications. On larger changes, an addendum may include revised pages, but the key formal instrument remains the addendum.

Therefore, in CSI-aligned bidding procedures, a substitution can be approved during bidding only when it is issued to all bidders as an addendum, making Option A the correct answer.

Key CSI-Related References (titles only, no links):

CSI Project Delivery Practice Guide – procurement process, bidder communications, and substitutions.

CSI Construction Specifications Practice Guide – Division 01 sections on Substitution Procedures and Instructions to Bidders regarding substitutions.

CSI CDT Study Materials – controlled substitutions during bidding and the role of addenda.