RIH & RAIH Application, Assessment and Certification 2025

Industrial hygiene, also known as Occupational hygiene, is a specialized field dedicated to anticipating, identifying, evaluating and controlling health hazards in the workplace. It plays a crucial role in creating healthier and safer work environments.

Industrial / occupational hygienists are professionals equipped with the necessary knowledge and skills in industrial / occupational hygiene. They play a vital role in safeguarding the health of the workforce against workplace hazards.

In Singapore, industrial / occupational hygiene professionals provide comprehensive services to manage workplace health hazards. This may include activities such as noise monitoring and control, air sampling and chemical hazard management.

The Registered Industrial Hygienist RIH (SG) and Registered Associate Industrial Hygienist RAIH (SG) Scheme is established by the Occupational and Environmental Health Society (OEHS), a non-profit organization dedicated to promoting and advancing occupational and environmental health in Singapore. The scheme is administered by the Registered Industrial Hygienist (RIH) Board set up by OEHS.

The RIH (SG) and RAIH (SG) certification scheme accredits industrial / occupational hygiene professionals practicing in Singapore. The main objectives of the scheme are to provide professional recognition, enhance standards, and improve the practice of industrial hygiene through continual learning and education.

The OEHS invites interested individuals who are industrial / occupational hygiene professionals or practitioners practicing in Singapore to apply for RIH (SG) or RAIH (SG).

Details of the application process and criteria can be found below. The deadline for the current application process is 12 September 2025. For any inquiries, please email oehsrih@gmail.com. We eagerly await your application.

Thank you.

Mr. Ang Boon Tian

President

Occupational & Environmental Health Society

Er.Chong Lee Mei

Chairman

Registered Industrial Hygienist Board

Application Process

RAIH (SG) application:

RAIH (SG) Application

RAIH registration requirements include a basic degree in occupational hygiene, engineering, science, or a related field. Experience requirements vary by qualification: candidates with an OH/IH degree need one year of practical experience, while those with non-OH/IH degrees or SDOH require two years. Professional competency will be assessed through an interview.

RIH (SG) application:

RIH (SG) Application

To qualify for RIH registration, candidates must hold a basic degree in occupational hygiene, engineering, science, or a related field. They must have completed a minimum of 150 hours of OH/IH coursework and possess at least 4 years of practical experience in OH/IH. Professional competency will be assessed through an interview.

Candidates must submit their application, including an IH coursework form and official university transcript, to the OEHS Secretariat. The RIH Board will determine the assessment path based on the applicant's qualifications. Those with an OH/IH degree will proceed directly to an interview, while those with Specialist Diploma in Occupational Hygiene (SDOH) or without a recognized OH/IH degree must first pass a written examination before the interview stage.

Two-Stage Application Process

The application process for both RAIH (SG) and RIH (SG) follows the same two-stage format. The RIH Board reviews applications to determine whether candidates proceed directly to an interview or require both written and oral assessments.

Stage A: Applicants must submit a completed application form electronically to oehsrih@gmail.com, including a signed and scanned final page. A non-refundable administration fee of S$ 150 is required, and applications must be submitted by 12 September 2025. The RIH Board reviews all applications and notifies successful candidates to proceed to Stage B.

Stage B: Depending on individual qualifications, applicants may be required to undergo a written examination (3 to 4 hours) followed by an oral interview (1 to 2 hours) or proceed directly to an oral interview. Generally, applicants with a recognized industrial/occupational hygiene degree/diploma, or those who are currently certified with an internationally recognized industrial/occupational hygiene accreditation program (such as BGC’s CIH, BOHS's COH, or AIOH's COH), will only be required to take the oral assessment. However, in exceptional cases, the RIH Board may require these applicants to undergo a written examination if there is relevant justification to evaluate their professional competence.

Written Examination

Candidates required to take the written examination will receive at least one month's notice to prepare. The RIH Board may organize preparatory briefing sessions for candidates. The examination comprehensively covers various industrial hygiene domains. Complete logistical details will be provided to eligible candidates.

Oral Examination

Candidates eligible for oral examination receive notification at least one month before their assessment date. As part of the interview process, candidates must prepare either a written paper or a PowerPoint presentation to demonstrate their professional competency. The OEHS Secretariat will provide detailed logistical information to eligible candidates.

Certification of RAIH (SG) or RIH (SG)

Successful applicants for the RAIH(SG) accreditation will be required to pay an accreditation fee of S$ 325 for the first five years.

Successful applicants for the RIH (SG) accreditation will be required to pay an accreditation fee of S$ 650 for the first five years.

Re-certification of RAIH (SG) or RIH (SG)

Applicants who have been successfully certified as RAIH (SG) or RIH (SG) must maintain their competency and act professionally as required by the current Code of Ethics (Appendix C).

Re-certification will be conducted every five years, and an RAIH (SG) or RIH (SG) can re-certify by meeting the re-certification criteria. The RIH Board will assess and approve re-certifications.

A re-certification fee of S$ 325 for RAIH(SG) and S$ 650 for RIH(SG) will apply.