Methodology

Who is included

A contractor is listed only when its own website shows all of the following:

1. Industrial refrigeration work on at least one of: ammonia (NH3/R-717), CO2 (R-744), industrial Freon/HFC, or glycol/brine. Passing mentions don't qualify, such as a sensor-calibration bullet, a testimonial or a project caption alone.
2. A published headquarters location (city and state). Companies that publish no address are not listed.
3. A working website and a published phone number.

Kitchen-equipment, walk-in-cooler and residential HVAC companies are excluded, and so is any company whose industrial refrigeration evidence is too thin to cite. An office of a firm that is already listed is shown as part of that firm, not as a separate listing.

Evidence standard

• Official sources only: the contractor's own pages. Every listing cites the pages used, and they are linked under "Sources."
• Systems, facility types and services (emergency repair, preventive maintenance, retrofits, controls, compliance documentation) are listed only when a cited page documents them.
• The "24/7 emergency service (published by contractor)" label appears only when a cited page uses explicit 24/7, 24-hour, around-the-clock or 365 wording. When it doesn't, the listing says the cited page does not publish a 24/7 claim. An after-hours phone number alone does not count.
• "States served" lists only states the contractor names or where it publishes an office.
• No inference: if something isn't published, we leave it out rather than guess.
• No ratings, reviews, rankings or verification badges.

Review and refresh

• Last checked: each listing shows the date its sources were last reviewed.
• Validation: new and changed listings go through a validated update process (schema and consistency checks) before the site is rebuilt.
• Rechecks: listings are rechecked periodically and when we receive a correction. A recheck may update details, replace dead source links, or hold a listing.
• Corrections: contractors and readers can email corrections, additions or removal requests to support@heritagerelay.com (see Contact).

Holds

A listing is held (removed from the site but kept in our records) when, for example:

• its website is offline or its headquarters can't be confirmed;
• its industrial refrigeration evidence is too thin under the rules above;
• it duplicates another listing (such as a branch with the same address and phone).

Held listings can return once the issue is resolved and they meet the rules again.

Independence

Listings are not paid, and there are currently no affiliate relationships. See About. Ammonia Crews is a trade name of Heritage Relay LLC, an Ohio limited liability company, and is not affiliated with RETA or IIAR.