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National Conference to Prevent Hearing Loss in Construction:


Address: Preventing Hearing Loss in the Construction Trades: A Best Practices Conference


Alternate description

MR. MEITL: Thank you, Scott.

Good afternoon, everyone. As you see, I represent a manufacturer - Caterpillar Inc.. I want to talk a little bit about a different aspect in terms of being the source of the noise. Our product does create noise in order to do its various tasks and applications. My speech does somewhat overlap with Scott's in some cases, but we will kind of work our way through that, as we did not prepare notes before we started.

As a little bit of an introduction, in the past, I think you are aware, construction equipment, in particular earth-moving equipment, which is mostly what Caterpillar makes, there used to be very little consideration given to noise and machines. The people who operated them actually felt it was just one of the outputs of the machine, as well as they looked at it in many ways as a means of evaluating the performance of the machine. They actually believed, and some people still do today, that if a machine is noisy then that means it is powerful and that it is performing properly, but that is not always true.

Things have changed. Things are moving now in terms of there are forces driving the reduction of noise on our machines not only from the regulation standpoint, but also from the commercial or market-driven type of forces. The customer's/users are requesting our machines to be quieter. Comfort is probably one of the biggest drivers in that in order to get people to operate the machines, they are looking for the machines to be comfortable, and noise does play a significant impact in that aspect.

I want to first talk about operator noise. I am showing on this chart, the four industry test standards that are used by manufacturers to measure operator noise on our machine. The bottom three listed, are standards that we use to compare "non-working" machine noise for specific conditions. Their primary use is for comparison purposes, to be able to test under controlled situations and get repeatable results to tell whether one machine is quieter than another machine. Basically, these were developed and are used by the industry to develop the machines.

The top one there, SAE J1166, is unique in that it is not measuring the noise doing just one specific task like the bottom three. It is actually measuring the machine noise during a simulated work cycle.

The simulated cycle is representative, but as you know with construction equipment, they do a lot of different tasks. The cycle does not include all tasks that machines do, but it does provide a good indication of the noise exposure the operator may experience in operating the machine for an 8-hour period.

At Caterpillar, we generally do have noise data based off of at least one of these standards. For newer products we do have this information in our marketing literature, and it is often in the operator's manual as well. So the noise information is generally available for our machine customers.

For most of our enclosed cabs, new from the factory, the sound levels are below 85 dB(A) when measured per SAE J1166. In many cases, and actually it is becoming more and more common, a high percentage of the machines are now actually in the mid-70's. I am even aware of some of our machines that are operating with operator levels in the 68 dB(A) range. So operator levels have come down. In general, they are below the 85 dB(A) activation levels for OSHA and MSHA for hearing conservation programs. This SAE J1166 is representative, but it may not indicate what the sound levels are for that machine at that specific job site when it is exposed to other environmental noise.

The cab is one of the key factors in reducing operator noise. The basic approach that has been taken is to isolate that operator from the noise source. One of the things that happens, is you put that nice air-conditioned cab on the machine, then people go out and operate it with the windows and doors open. Once they do that, the efficiency or effectiveness of that operator's station is lost, and he is now exposed to other external background noises that he may have been protected from when he was operating that machine with the cab closed. Also, often you find people have that nice quiet cab and then introduce their own noises inside that cab such as music systems, et cetera. It raises the noise level that person is exposed to because he always turns it up louder than the background noise he is hearing.

The key to keeping that cab system functioning and reducing the noise really is maintaining that cab, and Scott mentioned a few of these things. With a cab, the key is having it sealed, nearly airtight, with absorptive materials - headliners, floor mats, and isolation mounting to keep the structural noise from coming into the operator's station.

Now I want to talk a little bit about exterior noise. It is often referred to as environmental noise, but it is really the noise that the bystander or the people that are in that work area are exposed to. Like for operator noise, there are industry test standards that do exist for manufacturers to, again, measure the machines in controlled environments and be able to make noise level comparisons between machines. A caution relative to use of this standard test data in the field, the results are from very controlled test conditions, and once you take these machines out into an actual work site, the noise levels of those machines can vary substantially due to reflective surfaces. How far you are from the machine will determine the noise level you hear. We generally, for safety reasons do not like to have people close to the machines, but there are cases in doing specific tasks that they are. It is very site-dependent. The exterior noise values that we have available are measured to these test standards, but they only provide a level indication.

They cannot be used to say this is what that machine is going to produce at that work site. In fact, in none of these test conditions are the machines engaging the ground (moving material).

Machines have gotten environmentally quieter over the years. They continue to get quieter. There are reductions that I have seen in the 20 years that I have been at Caterpillar that vary from 2 to 6 dB(A). Many machines actually have available now, even in the U.S., sound reduction packages. As Scott mentioned, Europe has been one of the leading drivers in reducing exterior noise, and Caterpillar, being a worldwide company, has had to develop sound packages for many machines to meet those specific regulatory requirements.

Again, looking at some of the key factors affecting the environmental noise produced by the machines, it is very similar to the cab. The appropriate the sound materials, the sound panels, component isolation (engine enclosures) must be in place on the machine. Once they are removed or not maintained, significant affect on the noise level of the machine can occur.

Some of the primary noise sources vary substantially by machine type. With the engine and cooling system, one of the things that we have to sometimes remind people of is that, you cannot just seal those components up like you can a cab to keep the noise from escaping, because they do generate heat. You need airflow through those compartments to cool those components. So, as you are going through and you are looking at machine design or even retrofitting the machines, you have to look at the total system and make sure that you have a balanced design. That is one of the things that we strive to do in order to maintain efficiencies and the performance of the machine, while reducing the noise.

How the machine is operated, in many cases, may be more of a factor than the base noise produced by the machine itself. An example, if have a machine and it is loading gravel off of a concrete pad, every time that loader bucket runs across that pavement loading up that gravel, you will likely find the cutting edge, gravel and the concrete are making more noise than the base machine itself. You will not even hear the machine. Another example is of machines used with impact hammers. Breaking up concrete pavement with the hammer will make far more noise than the base machine itself.

With respect to the operation the machine does, it makes a significant difference when you try to come up with a total noise solution for the job site as you try to reduce the overall noise that is being generated. You not only have to look at the machine noise, but the noise caused by the materials being moved and the sound propagation at the site. Reducing the base machine noise may not result in any site noise reduction. You have to look at whether the site layout can be changed, do that work somewhere else. If it is a noisy task/work, do that work away from the exposed people. You may be able to attack the problem by putting up barriers like sound absorption walls or a berm. You can modify your work schedule, do the tasks at different times when there is not people around.

Machine cost is factor because it is in the cost equation for those people using the machines. It may not make any sense to buy a more expensive quieter machine because the task that it is doing is making more noise. You will need to take one of those other approaches.

There are other machine requirements that must be met, as an example, EPA is requiring reductions in engine exhaust emissions.

We have found that generally the viable solutions that we have identified to reduce exhaust emissions on construction equipment do impact in many cases the component noise levels. They are getting louder or being forced to get louder by other necessary package changes. We recognize that, and we are working on developing solutions that will reduce not only the emissions, but in doing so will be trying to maintain or continue to reduce the machine noise. There are tradeoffs and in many cases, this will not be an easy task.

To summarize, for operator noise levels, I can say Caterpillar machines are generally low, particularly for enclosed cabs. Most are below the 85 dB(A) activation level for OSHA General Industry and MSHA. One caution if the cab is what is used to reduce the operator's exposure, then it has got to be maintained and you need to keep it closed. Some machines are below the 85 dB(A), even without a cab, but once you put them on the job site and you have other background noise, the noise level that the operator is exposed to will likely increase.

For environmental noise, there are often lower-noise machines available. They have gotten quieter, and there are sound suppression options available for many of our machines. However, when you are looking at total site noise levels and people working around the machines, you have got to look at all the options and determine what is really the best solution for that specific site. Reducing base machine noise may not reduce the noise at all for that exposed laborer on that site.

Any questions?

PARTICIPANT: [Off mike.]

MR. MEITL: In general, it is low.

PARTICIPANT: [Off mike.]

MR. MEITL: It is going to vary substantially on the size of the machine. We offer a machine with 17 horsepower up to 1,000.

PARTICIPANT: [Off mike.]

MR. MEITL: Generally, and I do not have a good number, for a mid-sized machine, you are probably looking somewhere in the 3- to $5,000 type of premium over a standard machine.

PARTICIPANT: [Off mike.]

MR. MEITL: Like I say, it depends on the size, but for a mid-sized wheel loader, you are in the 150-, $200,000 range. So it is a small percent of the total machine cost. Yes.

PARTICIPANT: [Off mike.]

MR. MEITL: I am not aware of any, though when you talk about safety and backup alarms as an example --

PARTICIPANT: [Off mike.]

MR. MEITL: That is a possibility, yes.

PARTICIPANT: [Off mike.]

MR. MEITL: There are those tradeoffs.

MR. SCHNEIDER: Just to add something, there are communication systems now available with wireless communications so you can communicate with the cab operator pretty easily from everywhere on the site.

I do not know about studies with noise, and I think we need to do that, but they looked at, for example, one company in Sweden that developed a much more comfortable cab for the operator, and they did studies on productivity using the new cab and the old cab and found that people that use the new cab were much more productive because they are more comfortable than people using the old cab. So there was not really a tradeoff. They got more comfort and more productivity by these improvements, and I think we will see the same thing with noise. I think we will need to do some studies to look at what happens to productivity when you reduce the noise level. I will bet you, you are going to see an increase in productivity because people are more relaxed. They are more focussed on the job, et cetera. They are not as distracted by the noise. So I think it is going to be of benefit all the way around.


PARTICIPANT: [Off mike.]

MR. SCHNEIDER: I agree with you completely. I think there is a lot of stuff that could be done. A lot of it is not expensive. A lot of it is fairly simple, but it is not on the top of everyone's agenda. That is one of the purposes of this meeting is to say, hey, this is a huge problem, it is a serious problem, things can be done, it is not that difficult, let's start working on it.

Also, we will talk tomorrow a little bit at the session about two things. One of them is developing partnerships between the contractors and the manufacturers and the unions to promote this, to make sure that this is a higher-profile issue, and, secondly, to start working with the public so the public understands this is an important issue. You will see the materials out there that NIOSH has been producing on NIDCD (National Institute on Deafness), what they call the WISE EARS! Campaign, to really raise the increase of public awareness that this is a huge problem, things such as what Bill Duke talked on this morning, I think really to hit home and make it an important issue. The cover story we had in ENR last week, I think these kinds of things are the beginning of this public campaign. Frankly, people do not take it seriously because they see people getting killed on construction sites. This does not seem so important, but it is, and that is what I am hoping this conference, the publicity from the conference, before the conference and everything, will help.

I do not know what to do, but I think we are clearly committed to working on it with the manufacturers, with the contractors, the other unions, and that is what we hope to do over the coming years. Any ideas you have, we are open to it.

Does anybody else want to comment on this, how do we make this more important?


PARTICIPANT: [Off mike.]

MR. MEITL: The thing with vibration, it is going to be very machine-type-specific. An example is a bulldozer or track machine is going to have far more vibration than a rubber-tired machine. So it does vary substantially by the type.

There are very few. There may be some. I cannot think of any off the top of my head. Our machines where the operator station is isolated, does have isolation mounts to reduce that, and you have to do that. There are requirements, even in Europe, for exposure of operators to vibration. The vibration is a structural-borne vibration, coming up through there, amplifies noise, creates the noise in the operator's station. In terms of isolation, it is key to that, but in terms of what percent, it is hard.

PARTICIPANT: [Off mike.]

MR. MEITL: All larger machines do, yes.


MR. MEITL: That is the key. The operator has to adjust it properly.

MR. SCHNEIDER: Any other questions or comments?

PARTICIPANT: [Off mike.]

MR. MEITL: Again, in some cases, it may not reduce the noise level at the job site. So, in terms of what the customer sees in terms of the value he is getting, this job site is used to that machine. The other noises, that he is not getting any value for that. So the customer has to look at that.

PARTICIPANT: [Off mike.]

MR. MEITL: Not always, but, again, it depends on the type of machine. Some machines are at the bottom end of the quarry, and that is where it stays its whole life.

PARTICIPANT: [Off mike.]

MR. MEITL: Yes. I can say there are some machines we do not offer anything but a cab, but there are others that it is an option. The cabs can be standard, but the customers request that for specific conditions or their applications. They do not want a cab on that machine.

MR. SCHNEIDER: If there are no more questions, thanks for coming.

In about 10 minutes, there will be stuff out for break, cookies, coffee, and stuff like that. We have a little bit longer for a break, since we finished early, until about a quarter til. If you have time and you want to go up and look at the NIOSH van or get your hearing tested, that is out front. The hearing protection manufacturers are out in the lobby.

You should rotate to your next workshop, and you have the workshop rotation schedule. I do not remember if you guys are going over there or going over to the program workshop. It should be pretty interesting.

Thanks very much for coming.


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