Certification Overview

RETA certification requires meeting eligibility criteria and demonstrating knowledge of industrial refrigeration concepts, principles and practices.  RETA certification exams and other requirements assess competencies in the realm of industrial refrigeration operation. RETA training materials provide the fundamental knowledge needed to understand these concepts and operating principles.

The exams were developed based on surveys of experienced industrial refrigeration operators, managers and consultants. They also are consistent with recommended training objectives established in the Ammonia Refrigeration Training Guideline (ARTG) document developed in 2005, an industry project sponsored by RETA, IIAR and IARW in which benchmarks were established with regard to industrial refrigeration operation.


ANSI ACCREDITED markRETA certification exams are accredited by ANSI (American National Standards Institute), which requires that they are continually scrutinized by an organization whose sole mission is to establish, maintain and assure that the highest industry standards are set and met in a continuous and ongoing basis. ANSI is certainly recognized and often highly regarded by regulatory agencies such as EPA and OSHA in the establishment and maintenance of the highest industrial and safety benchmarks.

RETA’s ANSI accreditation assures to its members and industry that those who meet requirements to earn RETA credentials have met an established competence level to operate ammonia refrigeration systems in a safe and efficient manner.

RETA is fully committed to maintaining the fairness, impartiality, validity and integrity of all RETA certification programs. RETA policies and procedures are designed to assure that all decisions about certifying every candidate are based solely on the candidate’s qualifications and performance on RETA examinations and other certification-related activities.

Certification Levels

Currently offers two levels of ANSI accredited certification

CARO - Certified Assistant Refrigeration Operator 

CARO is an entry-level credential that is designed to demonstrate that an operator has sufficient knowledge to work under supervision in industrial refrigeration. There is no minimum experience requirement for CARO. The exam assesses mastery of concepts and principles in RETA’s Industrial Refrigeration I and the ammonia safety chapter in Industrial Refrigeration IV (chapter 7).


 CARO includes 110 questions and allows three hours for completion.


CIRO - Certified Industrial Refrigeration Operator


CIRO requires documentation of at least two years of experience as an industrial refrigeration operator. It assesses more advanced concepts, principles and applications required to supervise industrial refrigeration operations. CIRO measures mastery of applied refrigeration system operations and troubleshooting based on principles and knowledge addressed in RETA books: Industrial Refrigeration (IR) I · IR II (systems) IR IV (plant operation and safety) Basic Electricity (BE) I · Basic Electricity (BE) II (ladder diagrams).


 The CIRO exam consists of 135 questions and allows three hours for completion.


Other RETA Credentialing Programs

RETA also provides certification for three additional programs that are not ANSI-accredited.

CRST - Certified Refrigeration Service Technician

CRST was added on August 2018 and is designed for technicians and support personnel who troubleshoot and maintain industrial refrigeration plants and facilities.  The credential addresses topics from advanced levels of plant safety and operations through the basics of ammonia refrigeration compliance and PSM requirements. 

The CRST exam consists of 150 questions and allows three hours for completion.

A current RETA CARO or CIRO credential or 4 years of documented industrial refrigeration experience is required to take the CRST exam. Documentation must be submitted with the CRST exam application.

CRES - Certified Refrigeration Energy Specialist 

CRES was added in November 2013 to assess mastery of refrigeration system operations and energy management strategies. While no other RETA credentials are required to qualify for the CRES credential, CRES candidates do need to demonstrate sufficient knowledge of refrigeration operations to offer energy management strategies without compromising the safety or integrity of refrigeration systems.


 CRES candidates should be familiar with the operating concepts and principles addressed in IR-1 in addition to energy management strategies and techniques in the Industrial Refrigeration Best Practices Guide published by Cascade Energy and the Energy Conservation Manual – Industrial Refrigeration Consortium published by University of Wisconsin.


 The CRES exam consists of 135 questions and allows three hours for completion.


There is also a performance aspect related to CRES which includes the documentation of three energy saving activities related to refrigeration system operations and their facilities whereby energy savings can be quantitatively documented.


 Certification of CRES occurs after successful completion of the exam and documentation of three activities. Additional activities must be documented to maintain CRES certification.



RAI - RETA Authorized Instructor

This exam is designed to assess mastery of advanced refrigeration system concepts and operations at a level that qualifies a candidate to assist CARO, CIRO, CRST and CRES candidates with their preparations and activities required to earn RETA credentials. RAI candidates must demonstrate both teaching experience and knowledge of the content in all RETA publications that are designed to prepare operators and others to meet RETA certification requirements.

 The RAI exam consists of 85 questions and allows three hours for completion.

How long is my certification valid?

For all RETA certification programs, certification is valid for three years from test passage date or date of last three-year renewal cycle. RETA certification holders are notified of renewal requirements within one year of renewal date.

 Documentation of 24 Professional Development Hours (PDH) or 2.4 Continuing Education Units (CEU) is required to renew certification. (It is the certified individuals responsibility to collect and submit required documentation to RETA HQ.)

Click here for our Recertification page for more details


Certification Uniform Patches

Certification patches are available for a nominal charge. The patches are only available for those individuals that have a current RETA Certification. You must provide your Certification ID number when ordering patches.

Click here to order uniform patches online

Below is the paper Patch Order Form.

Patch Order Form

Item Name Posted By Date Posted
Patch Order Form PDF (45.35 KB) Administration 8/16/2018

Refrigerating Engineers & Technicians Association
Toll Free: 844.801.3711 · Phone: 541.497.2955 · Fax: 541.497.2966
1725 Ferry St SW, Albany, OR 97322