How Should Suppliers Declare Technical Deviations in a Tower Internals Quotation?

No supplier quotation is useful if the buyer cannot tell where the supplier has departed from the RFQ.

This is why a technical deviation list is one of the most valuable documents in engineered tower-internals procurement.

A supplier may have a valid reason for proposing something different.

The problem is not deviation itself.

The problem is undisclosed deviation.

What Is a Technical Deviation?

A technical deviation occurs when the supplier's proposal differs from the purchaser's stated requirement.

Examples include:

• different material grade;
• different sheet thickness;
• alternative packing model;
• different layer height;
• reduced documentation;
• changed inspection method;
• different segmentation;
• excluded support hardware.

Some deviations may improve the design.

Others may be unacceptable.

The purchaser cannot evaluate either case unless the difference is stated clearly.

Do Not Hide Deviations in General Notes

A supplier may write:

“Our standard design applies.”

This is not a useful deviation declaration.

If the purchaser requested 0.5 mm sheet and the supplier standard is 0.4 mm, the quotation should state:

RFQ requirement: 0.5 mmSupplier proposal: 0.4 mmReason: standard validated geometryImpact: lower packing weight; hydraulic data attached

That gives engineering something concrete to review.

Each Deviation Should Reference a Requirement

A strong deviation list identifies:

• RFQ clause;
• drawing number;
• datasheet line;
• purchaser requirement;
• supplier proposal;
• technical reason;
• commercial or schedule impact where applicable.

This avoids arguments later over whether the change was actually disclosed.

Alternative Design Is Not the Same as Noncompliance

Tower internals are often supplier-engineered products.

A supplier may legitimately propose:

• another distributor geometry;
• another segment arrangement;
• another support configuration.

If the RFQ permits vendor design, these alternatives should still be identified.

The purchaser can then decide whether the alternative satisfies the functional requirement.

Material Deviations Need Strong Control

Material substitutions are particularly important.

For example:

SS316L → SS304PVDF → PPvirgin resin → recycled blend

should never be hidden inside a commercial proposal.

The reason may be cost or availability.

But approval must come from the purchaser.

“No Deviation” Should Mean Something

If the supplier submits a statement saying:

No technical deviations

the buyer should be able to rely on that statement.

This means the supplier should have reviewed:

• drawings;
• datasheets;
• specifications;
• PO notes.

A generic “complies” line generated without detailed review provides little protection.

Clarification Is Different from Deviation

A clarification asks what the buyer means.

A deviation states what the supplier intends to do differently.

For example:

Clarification: Please confirm whether 150 mm is installed demister thickness.

Deviation: We propose 120 mm thickness instead of the specified 150 mm.

These should not be mixed.

Deviations Should Be Closed Before Manufacturing

The best time to resolve deviations is:

before the PO or before drawing approval.

Once fabrication begins, an unresolved deviation may lead to:

• rework;
• NCR;
• schedule delay;
• commercial claims.

Every important deviation should therefore reach one of three outcomes:

accepted,rejected, orsuperseded by revised requirement.

Accepted Deviations Should Enter the Final Baseline

If the buyer accepts an alternative, the final approved documents should reflect it.

Otherwise, the project can end up with:

RFQ showing one requirement and as-built equipment using another.

Future maintenance teams then have no reliable reference.

Supplier Benefit

A formal deviation list also protects the supplier.

If a different design was openly proposed and approved, the supplier should not later be accused of quietly failing to follow the original specification.

Transparent deviation management protects both parties.

Engineering Takeaway

Technical deviation control is not bureaucracy.

It is how a project distinguishes intentional approved differences from accidental nonconformance.

Every meaningful change from the RFQ should be visible, referenced, technically explained, and formally closed before manufacturing.