$700,000 to over $1,000,000 per year is the cost of back strains lifting iron manhole covers for just one medium-sized utility operation. This incredible data was given to CAP recently by a utility engineer; each incident costs $70,000, and they have 10-15 incidents for strains lifting covers each year. CAP composite covers weigh half to one-third of current iron covers and should certainly reduce, and hopefully eliminate, this issue.
"...it becomes clear that manual lifting of (cast iron) manhole cover is extremely hazardous and has the potential for inflicting very serious injuries."
- An Ergonomic Evaluation of Steel and Composite Manhole (Access) Covers, University of Cincinnati Ergonomics and Engineering Controls Research Laboratory
This type of lifting assist is a must for safe iron manhole cover lifting. But the average cost of $1,200 per unit and set up time should be considered as part of the added cost of iron. Plus, these devices do not address initial movement on and off a truck bed, but merely hole maintenance activities.
" ...over 36 percent of injuries involving missed workdays were the result of shoulder and back injuries. Overexertion and cumulative trauma were the biggest factors in these injuries."
Source: The Bureau of Labor Statistics
O.S.H.A. (29 CFR 1910.146) requires special procedures for confined spaces and describes a portal exit 24 inches or less "Restricted" for rescue service (Appendix F) . Since most standard manholes are 22 to 24-inch clear openings, the future holes will be larger than today's. 30-inch clear openings are now mandatory for new manholes in Texas, New Hampshire and an increasing number of states.
Density of Cast Iron= 7.2 grams/cubic cm
Density of Composite = 1.8 grams /cubic cm
That means for the same change in the cover size, the already heavier iron cover will increase 4 times more than the composite!!
Example: 125 lbs 26" iron cover might increase to 205 lbs for 32" cover while a composite cover of the same dimension would increase from around 75 lbs to 95 lbs - gaining 20 lbs vs. 80 lbs.