- Part Number:1926
- Part Number Title:Safety and Health Regulations for Construction
- Subpart:1926 Subpart W
- Subpart Title:Rollover Protective Structures; Overhead Protection
- Standard Number:
- Title:Protective frames (roll-over protective structures, known as ROPS) for wheel-type agricultural and industrial tractors used in construction.
- GPO Source:
When protective enclosures are used on wheel-type agricultural and industrial tractors, they shall meet the requirements of Society of Automotive Engineers ("SAE") standard J168-1970 ("Protective enclosures -- test procedures and performance requirements"), which is incorporated by reference. The incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.
SAE standard J168-1970 appears in the 1971 SAE Handbook, or it may be examined at: any OSHA Regional Office; the OSHA Docket Office, U.S. Department of Labor, 200 Constitution Avenue, NW., Room N-2625, Washington, DC 20210 (telephone: (202) 693-2350 (TTY number: (877) 889-5627)); or the National Archives and Records Administration ("NARA"). (For information on the availability of this material at NARA, telephone (202) 741-6030 or access the NARA Web site at http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.) Copies may be purchased from the Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, Pennsylvania 15096-0001.
The test shall be conducted on a dry, firm soil bank as illustrated in Figure W-15. The soil in the impact area shall have an average cone index in the 0-in. to 6-in. (0-mm to 153-mm) layer not less than 150 according to American Society of Agricultural Engineers ("ASAE") recommendation ASAE R313.1-1971 ("Soil cone penetrometer"), as reconfirmed in 1975, which is incorporated by reference. The incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. The path of vehicle travel shall be 12º 2º to the top edge of the bank.
ASAE recommendation ASAE R313.1-1971, as reconfirmed in 1975, appears in the 1977 Agricultural Engineers Yearbook, or it may be examined at: any OSHA Regional Office; the OSHA Docket Office, U.S. Department of Labor, 200 Constitution Avenue, NW., Room N-2625, Washington, DC 20210 (telephone: (202) 693-2350 (TTY number: (877) 889-5627)); or the National Archives and Records Administration ("NARA"). (For information on the availability of this material at NARA, telephone (202) 741-6030 or access the NARA Web site at http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html). Copies may be purchased from the American Society of Agricultural Engineers 2950 Niles Road, St. Joseph, MI 49085.
General. The frame shall be evaluated by imposing dynamic loading to the rear, followed by a load to the side on the same frame. The pendulum dropped from the height (see the definition of "H" in paragraph (j)(3) of this section) imposes the dynamic load. The position of the pendulum shall be so selected that the initial point of impact on the frame shall be in line with the arc of travel of the center of gravity of the pendulum. A quick-release mechanism should be used but, when used, it shall not influence the attitude of the block.
D = 2 in. (51 mm) inside of the frame upright to the vertical centerline of the seat;
E = 30 in. (762 mm);
F = Not less than 0 in. (0 mm) and not more than 12 in. (305 mm), measured at the centerline of the seat backrest to the crossbar along the line of load application as shown in Figure W-17; and
G = 24 in. (610 mm).
"Agricultural tractor" means a wheel-type vehicle of more than 20 engine horsepower, used in construction work, that is designed to furnish the power to pull, propel, or drive implements. (SAE standard J333a-1970 ("Operator protection for wheel-type agricultural and industrial tractors") defines "agricultural tractor" as a "wheel-type vehicle of more than 20 engine horsepower designed to furnish the power to pull, carry, propel, or drive implements that are designed for agricultural usage." Since this part 1926 applies only to construction work, the SAE definition of "agricultural tractor" is adopted for purposes of this subpart.)
"Industrial tractor" means that class of wheel-type tractors of more than 20 engine horsepower (other than rubber-tired loaders and dozers described in 29 CFR 1926.1001), used in operations such as landscaping, construction services, loading, digging, grounds keeping, and highway maintenance.
E is = Energy input to be absorbed during side loading in ft-lb (E'is in J [joules]);
E is = 723 + 0.4 W ft-lb (E' is = 100 + 0.12 W' , J);
E ir = Energy input to be absorbed during rear loading in ft-lb (E' ir in J);
E ir = 0.47 W ft-lb (E' ir = 0.14 W', J);
W = Tractor weight as specified by 29 CFR 1926.1002(e)(1) and (e)(3), in lb (W' , kg);
L = Static load, lb (kg);
D = Deflection under L, in. (mm);
L-D = Static load-deflection diagram;
Lm-Dm = Modified static load-deflection diagram (Figure W-20). To account for an increase in strength due to an increase in strain rate, raise L in the plastic range L x K;
K = Increase in yield strength induced by higher rate of loading (1.3 for hot, rolled, low-carbon steel 1010-1030). Low carbon is preferable; however, when higher carbon or other material is used, K must be determined in the laboratory. Refer to Norris, C.H., Hansen, R.J., Holley, M.J., Biggs, J.M., Namyet, S., and Minami, J.V., Structural Design for Dynamic Loads, McGraw-Hill, New York, 1959, p. 3;
Lmax = Maximum observed static load;
Load Limit = Point on a continuous L-D curve at which the observed static load is 0.8 Lmax (refer to Figure W-19);
Eu = Strain energy absorbed by the frame, ft-lb (J); area under the Lm-Dm curve;
FER = Factor of energy ratio, FER = EuEis; also, FER = EuEir; Pb = Maximum observed force in mounting connection under a static load, L, lb (kg);
Pu = Ultimate force capacity of mounting connection, lb (kg);
FSB = Design margin for a mounting connection (PuPb)-1; and
H = Vertical height of lift of 4,410-lb (2,000-kg) weight, in. (H', mm). The weight shall be pulled back so that the height of its center of gravity above the point of impact is defined as follows: H = 4.92 + 0.00190 W (H' = 125 + 0.107 W') (see Figure W-24).
Source of standard. The standard in this section is derived from, and restates, in part, Society of Automotive Engineers ("SAE") standard J334a-1970 ("Protective frame test procedures and performance requirements"). The SAE standard appears in the 1971 SAE Handbook, which may be examined at any OSHA regional office.
[61 FR 9227, March 7, 1996; 70 FR 76985, Dec. 29, 2005; 71 FR 41129, July 20, 2006]