National Conference to Prevent Hearing Loss in Construction:
P R O C E E D I N G S
Address: Preventing Hearing Loss in the Construction Trades: A Best Practices Conference
Director OSH, LHSFNA
MR. SCHNEIDER: We are starting a little late. We will go until about 2:30, about an hour and a quarter.
In putting this program together, we wanted to make sure that the message of this conference was not just, well, workers are having a lot of hearing loss, it is a terrible problem and they should wear more hearing protection. Althought that is one of the things we want to emphasize, we do not want that to be the sole message of this conference.
So we wanted to make sure that we included as one of our three workshops a workshop on noise control because, ultimately, that is the solution that we want to the problem of getting people to wear hearing protection which is uncomfortable. If the machines are quieter, presumably they do not have to wear it as much, or perhaps not even at all in many jobs.
This also solves the problem that some of the people that we were talking of earlier had, which was that of workers not being able to hear warning signs, not wanting to wear hearing protection because they are afraid they will not hear the warning signs. If the machines are quieter, that makes all of those problems either easier or they go away. So we really wanted to emphasize at this conference one of the aspects, which is noise control.
I guess I should introduce myself first. I am Scott Schneider. I am the director of Occupational Safety and Health for the Laborers' Health & Safety Fund of North America, which is sponsoring this conference, and we have two divisions, two program divisions, mine which deals with occupational safety and health and then there is the Health Promotion Division which tries to promote and improve laborers' health off the job, to get them to stop smoking, et cetera, and we have a lot of members at the conference and representatives and staff.
In talking about controlling noise, there is a number of ways to do it. One of them is to substitute a quieter process, totally redesign how the job is done. Second would be to substitute quieter equipment, and there is a variety of equipment in the marketplace and you will hear more about this later. Some of it is much quieter than others. Third would be to take the older equipment and retrofit it so that it is quieter. Fourth is to maintain the equipment properly which reduces the noise level from the equipment, and lastly, in terms of engineering controls, isolating the process or the operator. When I go through the rest of the slides, you will see examples of each of these types of controls.
Of course, there are also administrative controls. You can limit the time someone is exposed or perhaps rotate people through different jobs, through noisy jobs part of the day, quieter jobs the rest of the day, have restricted areas. If those areas are noisy, do not let people into those areas, if possible, unless they are wearing hearing protection or if they do not have to be there, and then also have rest breaks.
Some of these administrative controls are particularly difficult, though, in the construction industry where people are maybe doing certain jobs and they have to be in that area or it is really difficult to rotate them because there are not very many quiet tasks, et cetera.
Then, of course, lastly, there is the hearing protection approach where you use earplugs or earmuffs to reduce their noise exposure. In terms of the hierarchy of controls we always talk about, that is the last resort because, for a variety of reasons that we mentioned earlier, people do not want to wear them, it is uncomfortable, they cannot hear what is going on.
A lot of attention has been focussed on retrofitting old equipment, and I am sure Ken will talk about this some later as well. In particular, there was a lot of work done in the 1970's and 1980's on retrofitting bulldozers, frontend loaders, graters, scrapers, crawler tractors, vibratory rollers, joint cutters, and this is all published in the scientific literature. It is accessible. People have known about this for 20 years. A lot of it is not being done, but it is not that expensive. It is not that difficult to do, most of these things.
Some of the fixes are to add mufflers where you do not have one or to put a better muffler on, to add insulation to the cab which certainly reduces the noise level for the operator, but then it does not reduce the noise level for people outside the equipment, which is mostly the people that we represent, air-condition and pressurize the cabs, anti-vibration mountings, insulated covers over equipment that is going to absorb some of the sound.
In addition, for smaller equipment, for portable air compressors, pile drivers, pneumatic tools, circular saw blades, pavement breakers, there are enclosures that had been built for them. There has been treatments to the inlet or the exhaust for the air flow, to reduce the noise from the air. There are mufflers that exist. There is vibration damping. It also cuts down on the noise level.
For circular saws, there are slotted and stiffened blades that make a lot less noise than the old regular saw blades and expansion chambers for some of the gases that are being emitted from the pneumatic tools.
Alice mentioned earlier EPA back in the '70s, after the Noise Control Act was passed and the Quiet Communities Act, started putting out noise emission standards for construction equipment because they understood that this is the solution to our problems is that we need to start requiring that this equipment be made, manufactured, and sold in a quieter state.
Back in the late '70s, they put out a requirement that portable air compressors, I think after 1976, be manufactured with no more than 70 decibels being emitted. Lo and behold, the manufacturers met that challenge, and now the manufacturers are making quieter air compressors, and it makes a big difference on the job site.
They also put out a regulation for medium and heavy trucks to reduce the noise levels to 80 decibels, and this standard was put out in the late '70s. It got delayed four or five times until, I think it was, about the late '80s, like 1988, I think, that it finally went into effect.
There was a standard proposed for wheel and crawler tractors, a 74-to-80-decibel standard, depending on the power level of the truck, et cetera. That was just proposed. I do not think it ever went into effect, though.
In 1980, when Reagan came into office, the Noise Control Office of EPA was basically defunded. They have had zero funds for the last 19, 20 years. So, even though there is still an office, there is still a requirement under the Noise Control Act, there is really no money and no staff at EPA to enforce it or to put out any new requirements on other construction equipment.
There have been a couple of Congress people that have introduced proposed new bills to refund this office at $5 million a year, but so far, those bills have not been passed or have not gotten through the Congressional Appropriations Office.
As you will hear later, there are other construction noise standards that affect noise on the construction site. One of them in Germany, we will hear tomorrow about this Blue Angel Program which Charles Jeffress mentioned today, and there are European directives and requirements that quieter equipment has to be sold in Europe. You cannot sell noisier equipment in Europe, which is in some part driving the market for manufacturers, which is to say if I want to sell my equipment in Europe, I have to make quieter models. So they are putting a lot of energy and effort and research into making quieter equipment, and this is one of the driving forces.
Then, of course, there are local noise ordinances. This is an issue where you are doing construction work in an urban area, in a residential area, and there are a lot of concerns. They restrict noisy construction activities to certain hours of the day or to certain decibel levels at the edge of the site, and I think this is also going to be helping to drive people towards buying quieter equipment.
I want to give you some examples about how some of these things work. I put on the flipchart here an address for a web site in Australia. It is Safetyline. It is the web site for Work Safe Western Australia. The Australians have recognized this problem. They put a lot of time and energy into putting together materials. Just last October, they did a survey of building sites in Western Australia to see how noisy they were, what kind of noise controls were being used, what kind of hearing protection was being used.
They also said what people really like, what they really need to make progress, is to develop solutions, and we need to show people that there are solutions out there. So they have developed about a dozen case studies on their web site where they said here is the problem, here is what was done about it, and here is how much quieter it was after we made this change. So I am going to show you some of the case studies from their web site.
This is the one about noise control from a frontend loader. This is a Caterpillar loader. I do not know if Ken has seen this or not. It says the operating was operating at 90 decibels full idle and 82 low idle. They looked and said what can we do. This is exceeding their level of 85.
So they identified that the problem was engine and transmission noise through the cabin, through gaps in the seat, engine noise through open doors. It was not lined with acoustical lining. So this is where we are talking about retrofitting older equipment.
What they did was they made recommendations to add sound insulation to the cabin, the engine bay, and put sound absorbent materials on. What was the result? Reduction in noise to the operator. It was down to 85 on high idle and 76 for low idle. So you can see that is a reduction from 90 down to 85 and from 82 down to 76. That puts them down to a safe range, and it may not seem like a large reduction, 5 decibels, and in the low idle position of 6 decibels, but that is a huge difference in terms of sound power level.
PARTICIPANT: [Off mike.]
MR. SCHNEIDER: I am glad you asked. The approximate cost is $3,000, depending on the cab design and noise level. Then they give you the phone number. I do not know what you have to dial to get to Western Australia.
What is the difference between Australian dollars and U.S. dollars? That difference, I do not know. I should have looked that up. $1.60 is one Australian dollar?
PARTICIPANT: [Off mike.]
MR. SCHNEIDER: So then it is probably like $2,000, something like that. Good. Thank you very much. I should have looked that up.
Here is another example. A reciprocating processor was very noisy. This is an Ingersoll-Rand model. They said, "What can we do?" They improved the valve seating because they had a rough surface. It was sealed in poorly. They got new valves. Then they got polished, and they got a better seal. They added an oil additive to lubricate it and smooth out the finish on the cylinder. Other repairs were carried out, replacing the pressure gage and the guard.
What did they find? Sound measurements were taken. Measurements were taken one meter away. What did they find before maintenance? It was 94 decibels. After they replaced the valves and regrounded, it was 87. When they added the oil, it went down to 83.5, a huge difference. So it was an 8-decibel difference after they made all of these changes. Well, actually more. It was over 10 decibels. They do not have a cost estimate on this, but that does not sound like a very expensive fix.
PARTICIPANT: [Off mike.]
MR. SCHNEIDER: Here is another example, brick-cutting saws. Anyone who has been on job sites and sees them cutting bricks with circular saws knows how incredibly loud that is.
So they were measuring it here. They looked at this brick-cutting saw. They changed saw blades and put in a noise-reduced saw blade that was much stiffer, dampens the vibrations, and has a different teeth size, different teeth configurations. They found that the normal cut, it was 94.2 decibels for the operator, and 97, 1 meter off to the right. With the new noise-reduced blade, it was down to 83.9; 87, 1 meter away, so a huge difference. Also, if you read this text on the discussion, it says in addition, they found out that it takes 1.5 seconds with the regular blade for the noise to die out after you turn off the power. With the new noise-reduced blade, it died out after 140 milliseconds. So that is a huge difference.
I will give you a couple more examples from this Western Australia web site. They talk about other things. We talked earlier about using noise controls to change the process, and here, this one company, Johns Engineering Cranes, was changing their metal-cutting method for a low-noise one. They were using oxyacetylene cutting. It eliminated the need for further finishing, noisy angle grinders, et cetera.
Then, on the bottom, they mention another one. They changed the process. This contractor eliminated the use of hammers when installing or removing bearings. Before, they were knocked out with hammers. Now they heated or cooled these bearings in a pie-warmer, and they came right out and it reduced the noise tremendously. I will show you the data right here.
This shows pictures of them hammering the bearings out. Then they cool them in liquid nitrogen and they fit silently into the casing or they heat them in a pie-warmer. I guess they do not give the data. Here are some examples of substitution. They are really pushing this idea, which has been around a long time, but people have not implemented it much.
This is using Buy Quiet Programs to buy quieter equipment. What they do is they give examples here of alternatives. Instead of doing percussion riveting using compression and roll riveting, instead of drive-by compressed air, using electrical drive, instead of cutting shock punching using laser-beam cutting, et cetera, using water-jet cutting instead of a saw blade.
Here are some examples also using quieter equipment, 9-inch grinder on the left. It was noisier than a 4-inch one. Using a cutoff saw with a flexovit saw, it reduced the noise limits from 97 down to 92. Then, here at the bottom, they talk about pile driving using an impact sheet pile driver with noise levels of 105 at 5 meters and 96 at the crane. They replaced this method with a different pile-driving rig that emitted 95 decibels at 5 meters and 94 at the operator's position. Then they went to bore piling. Bore pilling was reduced to 90 at 5 meters. They replaced their portable generators with low-noise ones that went from 96 down to 78 decibels at 1 meter away.
Lastly, they just mention here another company. Instead of >using large jackhammers, they used smaller middle-range ones. That reduced the noise levels by about 10 decibels.
So just thinking about what to do and how you are going to do it and making simple changes and simple purchase decisions can make a huge difference.
There is a lot of information particularly about heavy equipment, and Ken is going to talk about this some in a minute, but I just wanted to mention some of these reports that I have.
For example, the Bureau of Mines has been very interested in this for many years. Back in 1980, they commissioned Bott, Beranek & Newman, which is a noise research company, to do studies on bulldozers and how we could control noise levels from bulldozers.
This is what they did to the bulldozer. This was a dozer. They added absorption. They added a muffler. They added a windshield.
I do not know how many jobs you have been out on, but you see these things and some of them are really in disrepair. They do not have doors. They do not have windows. They do not have a lot of stuff, but they added seals on the seat and around the dashboard, et cetera, floor mats with seals.
What was the result? They showed a reduction of 11 decibels. They had one dozer that had no cab and one with a cab. The reduction was 11 decibels. The material cost in 1978 dollars was about $500 to $800, about $1,000 to $1,200 for labor costs. The total cost was $1,500 to $2,000 to retrofit this bulldozer and to reduce the noise level by 11 decibels.
This manual that they produced actually gives you blueprints that shows you exactly how do you cut the insulation, where do you install it, et cetera, et cetera. So it is very detailed.
They did another one with a frontend loader, and these are basically similar kinds of treatment for this frontend loader, and here are the results. Basically, the total cost is $400 and 29 hours of labor. This also reduced the noise level by about 8 or 10 decibels. It was pretty
significant, especially when you think that a 10-decibel reduction is essentially a ten-fold decrease in sound power level. It is like one-tenth the amount of noise that you had before.
I wanted to mention this. Alice has already put up a slide about this. They did put out in 1983 a guide to machinery noise control for the mining industry, which uses a lot of the same equipment that we use. This handbook is very interesting because not only, as she showed you, does it have for surface mining equipment what the noise level was before they treated it and after. Here is one, for example, for crawler tractors. It shows you what they did, what you can do in terms of treatment, how to reduce the noise levels, how much it reduces the noise level, the cost in labor, and where you can get this. Most of these things are commercially available, and they actually give you a list here of commercially available noise-control products for use with crawler tractors, where you can get them, how much it costs, et cetera.
So it is a fabulous resource, and this is, I hope, one of the things we can do over the next couple of years is to develop something like this for the construction industry. That was 1983.
PARTICIPANT: [Off mike.]
MR. SCHNEIDER: I don't know. I think we need to research this again for construction and basically come up with a comparable kind of publication, a how-to thing. I do not know how much impact it has had on the mining industry, whether mining companies are going out and using this booklet or actually reducing levels. I have not seen any data in mining to see how much impact it has had, and maybe folks who have dealt with the mining industry or folks from NIOSH can tell us, but it is certainly a very handy, useful resource. That is what I like to see.
Anyway, that is what I wanted to present. I do not know if there are any questions about what I showed or anyone wants to say
MR. SCHNEIDER: No? Okay. Hang on one second.
Our next speaker is Ken Meitl who was born and raised on a farm in Kansas. He got his bachelor's degree in agriculture engineering from Kansas State in 1979, and then he joined Caterpillar in Peoria, Illinois, as a design engineer. For the last 20 years, he has been designing a variety of components and systems for Caterpillar machines, including projects to reduce noise levels. He is currently staff engineer for Caterpillar working on their regulations and product compliance group with responsibility for monitoring and communicating worldwide noise requirements for all mobile Caterpillar products to the respective machine business units.