Do You Guys Use Penetrometers?

MC Excavating

Do you guys use penetrometers?


For use by field personnel to check visual classification of soils. Verifies whether excavation side walls require shoring, based on OSHA cohesive soils classifications. Indicates consistency, shear strength, and approximate unconfined shear strength. Direct-reading scale—in tons/sq ft, or kg/sq cm-corresponds to equivalent unconfined compressive strength. Range: 0 to 4.5 tons.

I recently took a class and became certified for trench safety. This is a very helpful little tool to help you classify soil and then helping you to decide what type of safety precaution to take for you soil type. What degree of sloping, what type of benching, what type of shoring, or a shield. So far I think this is a very cool tool for $50.

denick

Is this a California thing???

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Nick

"Every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving" Albert Einstein

dayexco

they were promoting those when the extension service gave the competent person training course. i wouldn't be consistent enough to use it. we just pull a box "rated for 20' in type C soil", and be done with it, no matter what kind of soil we're in. i know we're bending the rules, but OSHA inspectors have seen it and never questioned it, but we always pull our box a foot to 18" off the trench bottom to save pipe bedding material.

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someday, i'll be as patient as Nick.

tgeb

I have never used one.
Just looking at them, I don't see how they could be very consistent. Sort of like a Kitchen scale...how do you calibrate the thing and how much could operator error effect the readings?

I can see it as an effective tool to show that you are taking due diligence, ie. you have tested and the reading was "X", you put that in your daily log and you are covered.

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Tom

www.gebcon.com

ch0mpie

Maybe they aren't very consistant, but you have to remember that nothing with soils or foundations is. I will tell you that engineers use there readings for design all the time and that if you get called into court about something and have a penetrometer reading in your log it won't look bad.

C buck

Never seen one, looks interesting. Seems like there would be alot of veriables though.

rino1494

IMO, experience with different soil types is worth more than that little tool.

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ch0mpie

I should add that results are typically only considered reliable for clays

MC Excavating

OSHA is nation wide thing. See article on soil classification.
Link: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10931

As far as getting certified in trench safety. It was a city thing. The city of South Pasadena, California required us to become certified in trench safety and first aid in order to get the permit to dig a basement.
Now I can no longer plead ignorance, now I know better and I'm now registered with OSHA for being a "Competent Person" for my company.

Definition from OSHA.

The term "Competent Person" is used in many OSHA standards and documents. As a general rule, the term is not specifically defined. In a broad sense, an OSHA competent person is an individual who, by way of training and/or experience, is knowledgeable of applicable standards, is capable of identifying workplace hazards relating to the specific operation, is designated by the employer, and has authority to take appropriate actions (29 CFR 1926.32). Some standards add additional specific requirements which must be met by the competent person.

This is simply a tool to help you classify soil condition and type. Now any time I excavate over 5' in depth I'm required to do some paper work to cover our butts and show that we take excavating safety seriously. In this paperwork there is a section to classify and note the compressive strength of the soil using a penetrometer, so I need to use this tool to do my paper work properly.

How many of you guys are the "competent person" for your company?

Have you or any of your employees taken any classes on trench safety?

This is something I always wanted to do but never had it set high enough on our priorities. So know we had to do it. Which I feel is a good thing.

dayexco

BUT, if an inspecter ever asks..."and they've yet to, knock on wood" can i see your soils logs....i'd have to tell him, ......i'll get back to you on that

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someday, i'll be as patient as Nick.

PipeGuy

Actually, a "thumb test" is a perfectly acceptable substitute for the pocket penetrometer; and you never need to worry about having left your thumb in the truck when you need it.
From 1926 Subpart P:
...(iii) Thumb penetration. The thumb penetration test can be used to estimate the unconfined compressive strength of cohesive soils. (This test is based on the thumb penetration test described in American Society for Testing and Materials (ASTM) Standard designation D2488 - "Standard Recommended Practice for Description of Soils (Visual - Manual Procedure).") Type A soils with an unconfined compressive strength of 1.5 tsf can be readily indented by the thumb; however, they can be penetrated by the thumb only with very great effort. Type C soils with an unconfined compressive strength of 0.5 tsf can be easily penetrated several inches by the thumb, and can be molded by light finger pressure. This test should be conducted on an undisturbed soil sample, such as a large clump of spoil, as soon as practicable after excavation to keep to a minimum the effects of exposure to drying influences.

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Fortunately I keep my feathers numbered for...for just such an emergency. -Foghorn Leghorn

PipeGuy

And another thing:
Being in the habit of continually monitoring soil conditions, whether you document it or not, is a lot more beneficial than doing it once a day and documenting it. In fact, as far as OSHA's concerned, you documenting an observation at 7:00 doesn't serve any purpose if the soil conditions change at 7:05.

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Fortunately I keep my feathers numbered for...for just such an emergency. -Foghorn Leghorn