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In this month’s installment, board-certified ergonomist Blake McGowan explains why the revised ACGIH Hand Activity TLV is a better predictor of hand, wrist, and forearm MSDs.

References:  American Conference of Governmental Industrial Hygienists (ACGIH) Worldwide, 2018. Threshold Limit Values for chemical substances and physical agents in the work environment. Cincinnati, OH: ACGIH Worldwide.

Video Transcript

Hi, my name is Blake McGowan, and I am a certified professional ergonomist with the HumanTech (now VelocityEHS Ergonomics).

One of the questions I get a lot from professional ergonomists and other experts is: What’s an excellent risk assessment tool for hand intensive activities, where I really need a deeper dive?

Well, the ACGIH hand activity threshold limit value, or TLV, is really an excellent tool to understand the level of musculoskeletal disorder, or MSD risk, for the hands, wrist, as well as the forearm. Actually, it’s a really good predictor of carpal tunnel syndrome, or CTS, even expressing a dose response relationship.

There are two inputs to the tool. The first one being the normalized peak hand forces, and the second one being the hand activity level. The output is a ratio, and that ratio is then compared to action limits, as well as the threshold limit value, and it helps you understand the level or the magnitude of MSD risk.

Well in 2018, it was made even better. Revisions were made that were based on key recent findings or research. Some of those key findings, or revisions include:

  1. is lowering the acceptable limits for the normalized hand peak forces, as well as the hand activity level.
  2. considering only forceful exertions that are at least 10% of your strength capabilities.
  3. is lowering the acceptable, as well as the unacceptable levels for TLVs.

So, what does this mean? What the bottom line? The bottom line is that the revised ACGIH hand activity TLV is now a better predictor of MSDS or carpal tunnel syndrome, and lastly it does a better job at protecting the global working population. So, for more information on HumanTech (VelocityEHS Ergonomics) and The Bottom Line series, please feel free to visit our website at HumanTech (now

Thanks, have a great day.