Ergonomics done right.®
January 29th, 2010

Q&A from the recent Hit List Webinar!

We recently hosted a webinar on the Ergonomics Hit List.
Thanks to everyone who participated. Some of you had questions we didn’t have
time to get to. See below for our responses.


Q: ­How was the optimal hand working height guideline (33" –
38" off the standing surface) established?­

The guideline was established
based off the standing hand working height of the 95th percentile
North American male (33" above the standing surface) and the standing elbow
height of the 5th percentile North American female (38" above
the standing surface).


Q: ­The majority of the slides showed production/fabrication
examples; can you give us some examples for the office environment­?

Humantech will be offering a
free webinar on office ergonomics and the four points of contact on March 31st.
More details will be posted on our web site shortly.


Q: ­I would greatly appreciate another webinar on office
ergo! Can you recommend a good (basic) book?­

There are a couple of books,
depending on your needs, worthy of considering:

“Office Ergonomics” by Kroemer
and Kroemer – an excellent book illustrated with drawings, case studies,
practical design recommendations that shows you how to correctly set up offices
both in work and home environments, select and arrange equipment and furniture
as well as tips on addressing environmental issues such as lighting, noise and
climate. Cost: Approximately $110.

 “Office Ergonomics: Practical
Applications” by Mckeown – this book contains practical advice and
demonstrations on how to design office environments that accommodate all
workers. Cost: Approximately $60.

 “Ergonomics in the Office
Primer" by Humantech – this quick reference book summarizes the key
information in the books listed above to help make your office a productive,
comfortable, and safe place to work by applying ergonomics principles. Cost:
$19.95. For more information, visit


Q: ­Our JSA's have and ergonomic evaluation portion.  Can we cut copy and paste the Hit List into
our JSA's to improve them?

Reproducing the Hit List images
to customize your company specific documents is a great idea, however; a license
to the materials is required as the information contained is proprietary to
Humantech and protected by copyright. 
Contact Kent directly at Humantech for questions on licensing.


Q: ­Sitting in relaxed position biomechanics say that the 12
lb of pressure per inch are reduced.  What is recommended for chair back
sitting posture?

Great question. There are few
parameters to consider that affect lumbar posture:

Seat height – A seat
pan which is too low rotates your pelvis which flattens the natural back curve.
Make sure your knees are slightly below your hips.

Back support – A
back support with a lumbar cushion positioned slightly above your pants belt
will promote improved low back postures. Ideally, the lumbar support should not
be greater than 2 inches thick. It is best to have a back support that is
adjustable in height and depth.

Back support tilt –
A back support and seat back rest tilt should be used in combination and can
significantly affect spinal disc pressures. For example, a lumbar support 2 inches
thick combined with a seat back support tilt angle of 120° results in low disc
pressure. The desired back support tilt angle range is between 100° and 120°.

Arm support – Disc
pressure is significantly reduced when the arms are supported by armrests and
the back support tilt angle is between 100° and 120°.