What's the number of concrete field testing technician grade 1 (ACI Level 1) per concrete placement?

[savvyj]

I work for an inspection and testing company that operates in NYC Metro Area (NY and NJ). Our clients sometimes request the very minimum number of inspectors and often it ends up in an exchange between parties to agree on a number of inspectors to be assigned.

My questions are the following:

1) How many concrete field-testing technician grade 1 (ACI Level 1) does a project need to perform field concrete inspections (sample sets) at the same location on a jobsite? (I believe this number should not be the same whenever the placement is for 50 cy to 1000 cy or more, or whenever a certain number of tests and sample sets performed; 1 v. 10).

2) Is there a reference or body of knowledge (from City, State, DOT, ACI, DOL, etc..) that shares some light into the number of concrete field technicians needed for number of cubic yards to be put in place or number of tests that are performed at each placement location?

I understand that this answer depends on the frequency of these tests but from the efficiency and energy of the individual performing these tests I see it as something that cannot be left to interpretation. Also, if you consider the possibility of overtime concrete that requires sampling and testing due to "unforeseen" conditions.

Assume each sample set is composed of 12 to 20 cylinders.

 

[TigerGuy]

The number of technicians depends on the testing frequency and the speed of placement. If the project specs call for a set of cylinders on every truck, and they are emptying a truck in 10 minutes, you need enough people to keep up. If they need a set every 100 cubic yards, and they are pouring 75 cubic yards per hour, a single tech should be able to keep up.

Some projects require slump and air on every load, which requires more personnel.

Outside of that, you may have a trainee on site from time to time, but there is no set number of people required.

 

[darthsoilsguy2]

I did this for about 10 years. It's a case-by-case decision. MOST of the time jobs only required 1 technician, including jobs with sets every 50. We knew when we would have to staff more, but we would get that sense from everything leading up to the pour and the info we would get about the pour. There is usually a bottleneck on the contractor's side that prevents them from dumping it all at once and you'll need to identify those constraints. Often times additional techs were staffed when extra testing was required or there was a contractor who was very particular about the way tests were done. I've had jobs where people wanted every truck slumped and chase-metered and done at the beginning of the truck, not the middle-third where we did our composite sample tests. When you have a job that the technician is actually holding up the job, it costs a lot more money to understaff the job. Usually the Owner pays for testing, not the contractor, so if there is a real risk of holding up the concrete pour and costing the contractor lots of money.... the contractor will come to bat for you to have a 2nd tech. I don't know of a reference you are looking for, but I would not think one would be available except possibly in the DOT world which likes to have procedures on everything. i don't think it would exist because it is hard to develop a written practice to identify contractor bottlenecks and how they interact with the project specs. just too many variables.