English specification desk How guides are written

Home / HVAC / How to specify a Duct Fitting

HVAC

How to specify a Duct Fitting

What to put on an RFQ for Duct Fitting: the ratings, documents, and constraints that change the quote.

25 Oct 2026 · 3 min read · Tradinor Desk

Specification points for Duct FittingTRADINOR · FIGUREWhat to lock for Duct FittingInstallationNoiseCapacityAir or water
Put these on the RFQ for Duct Fitting before you compare prices.

A buyer searching for Duct Fitting is usually trying to stop a bad substitute. HVAC equipment is specified by capacity at a stated condition, the refrigerant or fuel, the air or water flow, and the noise. The notes below are selection criteria for a Duct Fitting. They are not a catalog promise. Confirm every rating on the current datasheet, drawing, or test report for the revision you will receive.

What has to be true of Duct Fitting

HVAC equipment is specified by capacity at a stated condition, the refrigerant or fuel, the air or water flow, and the noise. For a Duct Fitting, start from the duty, then the interface to the rest of the machine or the room, then the document that proves the claim. A lower price that leaves one of those blank is a different product.

Duct Fitting is easy to confuse with Evaporator Coil. If the quote could be read as either, add the line that separates them: the rating, the fitment, or the standard named below. Link the drawing number to that line so receiving inspection can reject the wrong one.

Numbers that change the quote

Line What to write for Duct Fitting
Installation Split, packaged, or a terminal unit, and the clearance.
Noise The sound figure at a stated distance.
Capacity Cooling or heating at the outdoor and indoor condition, not only a nominal ton.
Air or water Airflow or water flow and the pressure drop.
Electrical Voltage, phases, and the starting method.
Refrigerant or fuel The fluid, as the market allows. Handling it is a licensed job, not a note on this page.

How to compare two offers

Lay both quotes for Duct Fitting on one sheet and line up installation, noise, and capacity. If a cell is empty, the offer is not finished. Ask for the missing line in writing. When those match, the honest difference is lead time, the test evidence, and who carries the warranty. Do not average a fully specified Duct Fitting with a cheaper line that omitted installation.

Documents worth having before the deposit

Ask for the capacity at the design outdoor temperature. The file should name Duct Fitting and the revision, not only the supplier’s homepage. A factory quality certificate such as ISO 9001 can sit beside that file. It does not replace it.

Failures that show up after delivery

  • Treating refrigerant work as a purchasing checkbox.
  • Buying nominal tons and discovering the derate on a hot day.
  • Ignoring duct or pipe pressure drop.

On a Duct Fitting, the expensive version of the first mistake is discovering it after the goods are in the crate. Put the rejection condition in the purchase order while the supplier can still restate the offer.

A worked RFQ line

Use this shape, then replace the brackets with your duty: “Duct Fitting — State capacity at a condition, airflow or water flow, electrical supply, and noise.” That sentence is a template, not a rating of any brand. If a supplier’s datasheet uses different units, convert them onto this sheet so the next offer can be compared.

Where words like RoHS / CE belong

Searches often add a constraint to Duct Fitting: RoHS / CE, or explosion-proof / ATEX. Keep those on this page. RoHS is a material limit. CE is a declaration that lists the rules relied on. Ask for the document that names this part number and revision. ATEX or IECEx is a certificate for a zone, a gas or dust group, and a temperature class. An IP rating does not grant it. Skip the mark if the site is not hazardous. If you need a third constraint, add it as another line on the same drawing. A second URL that only swaps the adjective does not give a buyer a second fact.

Related in this section: how to specify Evaporator Coil.

Questions buyers actually ask

What should an RFQ for Duct Fitting include?

State capacity at a condition, airflow or water flow, electrical supply, and noise.

Is a cheaper Duct Fitting the same part?

Only if installation, noise, and the documents match. A missing line is a different offer.

Do waterproof, OEM, or IP words need their own page?

No. For Duct Fitting they are extra lines on this specification. Ask for the test or the drawing that gives the word a value.