South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange South Dakota State University Agricultural Bulletins Experiment Station

10-1-1970 Quiet Your Noisy Tractor P. K. Turnquist

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Recommended Citation Turnquist, P. K., "Quiet Your Noisy Tractor" (1970). Bulletins. Paper 580. http://openprairie.sdstate.edu/agexperimentsta_bulletins/580

This Bulletin is brought to you for free and open access by the South Dakota State University Agricultural Experiment Station at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Bulletins by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. Bul,letin 577 October 1970

QUIET Your Noisy Tractor

Agricultural Experiment Station, South Dakota State University, Brookings. CONTENTS

Soundproofing the Tractor Cab______4

Aco us t ica I Ear Muffs______7

Other Ways to Help -Reduce Tractor Noise ------8

What to Expect______9

So,urce of Materials ______l O

Technical References ______l O

Reprint lM -- 2-70 -- 1271 2 QUIET Your Noisy Tractor

, by PAUL K. TURNQUIST Associate Professor Agricultural Engineering

Agricultural machinery noise is Most South Dakota farm tractors not only bothersome, it can be tested make enough noise to be downright unhealthy. potentially dangerous to hearing; But it can be reduced by providing that is, they operate at levels above a suitable barrier between the source 85 decibels. of "unwanted sound" and the ear. To get an idea of how this 85- One way is to properly soundproof a decibel level compares with other tractor cab. Another way is to use sounds consider: ordinary con­ acoustical earmuffs. Both methods versation is rated at 60 decibels; 70 have advantages and disadvantages; decibels is the level of an average soundproofing a cab costs about radio; 80 decibels for heavy street $100, a pair of earmuffs costs traffic or factory noise; 90 decibels around $7. for a pneumatic drill, some food Loud noise, such as that from blenders, loud radio, noisy street; many tractors, has been shown to be and 95 decibels for an open car injurious to hearing. Prolonged and window near the ear. Frequent and frequent exposure to such noise may prolonged exposure to loud noise is cause permanent hearing loss. to be avoided. Additionally, some investigators Here are some danger signals: report "... noise above 85 decibels your ears ring or. you experience at a certain pitch is now considered a head noises for a few hours after you medical hazard and can affect the get off the tractor following a day's heart, lungs, blood pressure, nervous work. Another clue is that your system, and eventually every body speech seems to be muffled when function." Noise is also classed as a you talk after being around loud pollutant. noise for an extended period. How do I know that my tractor is The onset of these hearing too noisy? problems is gradual and insidious. Engineers can measure sound Teenagers and young people on with special equipment. But you'll farms and ranches exposed to ex­ likely not have such equipment cessive noise levels may be asking for available to test your tractor. One hearing trouble later in life. type of sound measurement unit is Prevention is the best treatment and the decibel. Engineers and others it must start in the teens. Periodic have set 85 decibels as an acceptable routine hearing tests of persons in level-that is, a level of sound noisy occupations can help prevent beyond which they consider damage many cases of deafness, according to to hearing is likely to occur. physicians. 3 Soundproofing the Tractor Cab

A tractor cab itself doesn't the sound to acceptable levels. The necessarily mean noise will be I-inch thickness was somewhat more reduced. In fact, research indicates effective-and more expensive. that the uninsulated tractor cab A rubber foam adhesive is best for often tends to amplify the noise and attaching the acoustical material in it becomes even louder than without the cab. A heavy duty scissors the cab. Addition of acoustical foam readily cuts the acoustical foam. to the walls and ceiling and under the floor mat reduced noise levels to INSTALLATION safer values in research at the The acoustical foam should be Agricultural Experiment Station at South Dakota State University. This installed on the cab ceiling and on the metal portions of the walls and type of soundproofing can be done doors. The console and other ex­ by the tractor owner. He often can posed parts, including the floor, do a better job in sealing openings, should also be covered. If possible, especially in the floor, than the place fiberglass insulation (building manufacturers since it does require type) inside the console to act as some customized fitting. firewall. MATERIAL NEEDED It is important to cover all exposed metal surfaces and to close all holes. Acoustical foam with perforated Since many irregular shaped pieces vinyl facing turned out to be the best of material must be cut to fit inside sound absorbing material of several the cab, templates or a "pattern" of tested from the standpoint of ef­ heavy paper will help to eliminate fectiveness, being easier to apply, guessing on sizes and shapes of and being more practical after in­ various pieces as well as to reduce stallation because the surface was need for trimming the acoustical less likely to be damaged from foam. Templates are used to trace "scuffing." The vinyl facing also size and shape on the acoustical accumulates less dust. material-a ball point pen does this Two thicknesses of acoustical very well. Follow directions on the foam (I-inch and Y2-inch) were used label of the adhesive material you in the experiments and both lowered use.

This is the type of perforated vinyl­ faced acoustical foam used in the soundproofing study. The vinyl faces out when installed. Although the 112- inch thickness gave satisfactory results, the I-inch thickness was better. Thickness of insulation is a factor in noise reduction. 4 This type of rubber floor mat was used in the experiments for "step­ ping" parts of the cab. It is a sound harrier type of floor mat five­ sixteenths of an inch thick. However, any good quality rubber floor mat placed over the acoustical foam also is satisfactory.

A template or pattern made from heavy paper and the 1/z-inch acoustical foam panel cut from it with a scissors.

The floor mat was placed over the acoustical foam. Other exposed parts, including the seat pedestal as shown here,_must also pe covered with foam or floor mat for most effective soundproofing.�

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5 • Tractor console covered with 1/z- inch acoustical foam. If possible, place building-type fiberglass in­ sulation inside the console.

Boards may be fitted to help support the ceiling installation until the adhesive sets sufficiently. 6 Acoustica I Ear Muffs

Research using lightweigh_t, acoustical ear muffs was m cooperation with a group of farmers. Members of the group tried the ear muffs under various field conditions to establish some of the practical aspects of this method of protection from loud noise. All tractors driven by this group operated at excessive noise levels. Ear muffs reduced noise to comfortable and acceptable levels in all cases. Some cooperators ex­ perienced physical discomfort from wearing the ear muffs but they indicated they would rather wear the · ear muffs than be subjected to the excessive noise. Even if not worn 100 percent of the time, ear muffs help reduce the threat of hearing loss due to tractor and agricultural machinery noise because they aid in avoiding prolonged exposure. Operators claimed that after a short time they became accustomed to the ear muffs and suffered less discomfort. Additional findings indicated these items affect ear muff use: type of field operation, frequency of dismounting the tractor, temperature, and length of time the ear muffs are worn.

Interior of cab with 1/z-inch ·foam soundproofing.

This is the type of adjustable lightweight acoustical ear muff used in the agricultural machinery noise research. 7 Other Ways to Help Reduce Tractor Noise

By themselves, the sound sup­ combined with soundproofed cabs. pressing methods pictured below did They are included here to illustrate not reduce noise to acceptable levels additional ways in which noise may although they were helpful when be reduced.

An extension to a factory replacement muffler directs noise over and above the tractor cab. After you extend the exhaust upward, don't drive out of your shop without first measuring the height of the door.

An exhaust snubber mounted at 45- degree angles toward side and front of tractor tends to reduce and deflect exhaust noise away from the operator. This is a large volume muffler of the type often used on stationary engines and costs about $50. It must be in­ stalled so as to not obstruct the view from the cab.

8 What to Expect

Let's say you effectively insulate In the case of using ear muffs, you the inside of your tractor cab for "learn" to wear them. One noise reduction. That's fine for cool cooperating farmer reported that at days. But at certain seasons the first the ear muff gave him a inside of the cab is so hot you cannot sensation of going around with his operate the tractor in comfort even head under water. Ear muffs usually with a pressurized cab. If you open a can be adjusted to relieve discomfort window for ventilation, you undo all from side pressure on the head. How or most of your sound conditioning about using ear muffs with radios? effort. Depending upon how much One operator placed small speakers you value your comfort and your inside the ear muffs. Others plug in hearing, the next step is air con­ the individual hearing device that ditioning. Some researchers, in comes with many radios and wear commenting on fixing up your the ear muffs over it. present tractor . or in considering Researchers are serious when they purchase of a new one, suggest that suggest that you think twice before you think of a "package" deal: overhauling your tractor after convenience, safety, comfort, less putting on sound deadening devices. noise, air conditioning. The reason: special exhaust muf­ flers, or insulated cabs, or ear muffs, may tend to mask customary noises so that other "new " sounds become This tractor used I-inch fiberglass more noticeable. These new or (in this case) adhered to underside of hood ( dismounted, foreground) and different sounds may mislead you to the firewall plus soundproofing the into thinking something is wrong cab. with tractor or attachments.

9 Source of Materia Is

The following sources of materials Company of Pittsburgh, Penn­ are not intended to be an all in­ sylvania. They were obtained clusive list-other sources un­ through the branch office at 3018 doubtedly are available. No en­ East Lake Street, Minneapolis, dorsement of specific products or Minnesota 55406. equipment named is intended, nor is Another source of the ear muffs is criticism implied of those not the Mechanized Agriculture Club, mentioned. Agricultural Engineering Building, South Dakota State University, CAB SOUNDPROOFING Brookings, South Dakota 57006 . The Club established a project to Vinyl-backed acoustical foam alert farmers to the dangers of ex­ usually is sold by the foot or square cessive machinery noise and also foot from rolls. Rolls 54 inches wide make ear muffs available for those for the acoustical foam are available. desiring to purchase them. About See your implement dealer or five months after the campaign contact the Egging Company, opened the Club had received orders Gurley, Nebraska 69141. for more than 1,800 ear muffs, Any good quality rubber floor mainly from a dozen Upper Midwest matting material is suitable. A states. recommended adhesive is 3-M 4500 or equivalent. Templates may be made from Other sources for acoustical ear ordinary brown wrapping paper or protection are: by splitting the large, heavy sacks from the supermarket. American Optical Corporation 3018 Aurora Avenue Des Moines, Iowa 50310 ACOUSTICAL EAR MUFFS The acoustical ear muffs used in Wilson Products Division these experiments were manufac­ 1985 Janice Avenue tured by Mine Safety Appliance Melrose Park, Illinois 60160

Technica I References For technical information on the subject see: "A Method for Characterizing Agricultural Tractor Noise in Terms of Acoustic Power and Directivity, " by T. S. Chisholm and P. K. Turnquist, Transactions of the ASAE, Vol. 12, No. 5, pp. 591-594, 1969. "Effect of Cab, Soundproofing, and Exhaust-Control Methods on Tractor Noise at Operator's Site," by D. W. Ryland and P. K. Turnquist, Transactions of the ASAE, Vol. 13, No. 1, pp. 148-150, 152, 1970. "Evaluation of an Acoustical Ear Muff for Agricultural Tractor Operators, " by Harlin J. Trefz, M. S. Thesis, South Dakota State University, 1969. 10 ,

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