What is the EN689 Workplace Testing Standard?
EN689 is one of the methods that WorkSafe New Zealand recommends for workplace surveys. This is used to measure personal exposure to chemical agents and applies only to inhalable contaminants.
This standard includes the following steps:
- Identifying contaminants in the workplace
- Determining similar exposure groups (SEGs) and coming up with sampling plan (scoping for larger sites is often done as a separate project)
- On-site testing
- Validating the results and running a statistical test to determine compliance
How often do I need to do testing?
Compliance testing is similar to a Warrant of Fitness for a car. Testing is required at regular intervals to ensure workplaces are operating safely.
The retesting interval is determined on the results of testing. The interval could be between 6 months to 5 years.
What is the benefit of this compared to previous testing we have done?
This of course depends on what testing was previously done. The EN689 standard is a good way to ensure people are not missed who have potentially high results. Personal monitoring is key in identifying an SEGs exposure to contaminants.
What is an SEG?
An SEG is a group of workers with a similar exposure profile. Often this is wrongly interpreted as groups of workers carrying out similar tasks. In practice, even workers working in the same area may have different exposure profiles due to differences in individual behaviour.
Therefore, correct identification of similar exposure groups is crucial at early planning stages and may help to avoid unnecessary retests.
What is a statistical test?
Due to natural variation, exposure measured on a single day may not reflect exposure on other days. Testing each worker every day is impractical.
However, in most cases we are able to find a pattern in exposure based on a few samples. Once the pattern is known, statistical analysis can predict how likely a worker is to have unsafe levels of exposure.