Guide · Alternates
How to get a lighting "or equal" substitution approved
An alternate gets approved when the reviewer can see in two minutes that the design intent survives. Here is how to show that.
Short answer
Present the alternate side by side with the specified product, attribute by attribute: delivered lumens and distribution (compare the IES files), CCT, CRI and colour consistency, dimming protocol and range, input voltage, dimensions and mounting, finish, certification and location ratings, warranty and lead time. Show where it is equal, where it is better, and state plainly where it differs. Submit it through the project’s substitution procedure, usually before the product submittal.
Key takeaways
- Compare delivered performance from IES files, not catalogue headlines.
- Disclose differences; hidden differences get the whole package rejected.
- Follow the project’s substitution procedure and timing.
- Lead time and budget are legitimate reasons, but the design intent must hold.
What to compare
| Attribute | Compare using | Equal means |
|---|---|---|
| Delivered lumens | IES files, same length | Within a small tolerance of the basis of design |
| Distribution | IES candela plots | Same type (e.g. direct/indirect split, wall-wash throw) |
| Glare | Lens type, UGR or shielding data | No worse |
| Colour | CCT, CRI, R9, MacAdam steps | Same CCT; CRI and consistency no lower |
| Electrical | Input voltage, driver, dimming protocol and range | Same protocol; same or deeper dimming |
| Physical | Profile, length rules, aperture, mounting | Fits the same ceiling and details |
| Compliance | Certification mark, location rating | Meets or exceeds |
| Commercial | Warranty, lead time, price | Stated plainly |
How to present it
- One page per type: specified product on the left, alternate on the right, attributes in rows.
- Mark each row equal, better or different; explain every “different” in one line.
- Attach both IES files and both cut sheets.
- State the reason: lead time, availability or budget, with numbers.
Timing
Submit substitutions when the project’s procedure requires, often before or with the first product submittal. Late substitutions are more likely to be rejected because the design team has less time to review them.
Frequently asked questions
When should I not propose a substitution?
When the specified product is part of a visible, coordinated design (for example a signature pendant or a trimless detail built into millwork), when the specification prohibits substitutions, or when the alternate cannot match a performance requirement.
Where are substitution rules found in a specification?
Usually in the general requirements (substitution procedures) and in the lighting section itself. In MasterFormat-based specifications these are Section 01 25 00 and Section 26 51 00 for interior lighting.
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