Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-155 - Safety standards for construction work › Part V - ROLLOVER PROTECTIVE STRUCTURES AND OVERHEAD PROTECTION › Section 296-155-960 - Protective frame (ROPS) test procedures and performance requirements for wheel-type agricultural and industrial tractors used in construction

Current through Register Vol. 24-14, July 15, 2024
(1)
Definitions applicable to this section.
Agricultural tractor. As defined by SAE J333a, Operator
				  Protection for Wheel-Type Agricultural and Industrial Tractors (July 1970), 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 chapter applies only to construction work, the
				  following definition of "agricultural tractor" is adopted for purposes of this
				  part: "Agricultural tractor" means a wheel-type vehicle of more than 20 engine
				  horsepower, used in construction work, which is designed to furnish the power
				  to pull, propel, or drive implements.
Industrial tractor. That class of wheeled type tractor of
				  more than 20 engine horsepower (other than rubber-tired loaders and dozers
				  described in WAC
				  296-155-955 ), used in operations
				  such as landscaping, construction services, loading, digging, grounds keeping,
				  and highway maintenance.
* The following symbols, terms, and explanations apply to
				  this section:
Eis = Energy input to be absorbed
				  during side loading. Eis = 723 + 0.4 W ft.-lb.
				  (E'is = 100 + 0.12 W', m.- kg).
Eir = Energy input to be absorbed
				  during rear loading. Eir = 0.47 W ft.- lb.
				  (E'ir = 0.14 W', m.- kg).
W = Tractor weight as prescribed in WAC
				  296-155-960(5)(a) and
				  (5)(c) 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 V-20). To account for increase
				  in strength due to increase in strain rate, raise L in plastic range to 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, if higher carbon or other material is used, K must be
				  determined in the laboratory. Refer to Charles H. Norris, et al., Structural
				  Design for Dynamic Loads (1959), p. 3.
Lmax = Maximum observed static
				  load.
Load limit = Point on L-D curve where observed static load is
				  0.8 Lmax (refer to Figure V-19).
Eu = Strain energy absorbed by the
				  frame, ft.-lb. (m. - kg) area under
				  Lm-Dm curve.
FER = Factor of energy ratio, FER =
				  Eu/Eis; also =
				  Eu/Eir.
Pb = Maximum observed force in
				  mounting connection under static load, L, lb. (kg.).
FSB = Design margin for mounting connection FSB =
				  (Pu/Pb)-1.
H = Vertical height of lift of 4,410 lb. (2,000 kg.) weight,
				  in. (H', mm.). The weight must 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 or (H' = 125 = 0.107 W') (Figure V-14).
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				  here to view image
FIGURE V-14
Impact energy and corresponding lift height of 4,410 lb.
				  (2,000 kg.) weight.
Note:
The standard in this section is derived
						  from, and restates, Society of Automotive Engineers Standard J334a (July 1970),
						  Protective Frame Test Procedures and Performance Requirements. This standard
						  must be used in the event that questions of interpretation arise. The standard
						  appears in the 1971 SAE Handbook.
(2)
General.
(a) The purpose of this
				section is to set forth requirements for frames for the protection of operators
				of wheel type agricultural and industrial tractors to minimize the possibility
				of operator injury resulting from accidental upsets during normal operation.
				With respect to agricultural and industrial tractors, the provisions of WAC
				296-155-955 and
				296-155-965 for rubber-tired
				dozers and rubber-tired loaders may be utilized in lieu of the requirements of
				this section.
(b) The protective
				frame which is the subject of this standard is a structure mounted to the
				tractor that extends above the operator's seat and conforms generally to Figure
				V-15.
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				  here to view image
FIGURE V-15
Typical frame configuration.
(c) If an overhead weather shield is attached
				to the protective frame, it may be in place during tests: Provided, That it
				does not contribute to the strength of the protective frame. If such an
				overhead weather shield is attached, it must meet the requirements of
				subsection (10) of this section.
(d) For overhead protection requirements, see
				WAC 296-155-965.
(e) If protective enclosures are used on
				wheel-type agricultural and industrial tractors, they must meet the
				requirements of Society of Automotive Engineers Standard J168 (July 1970),
				Protective Enclosures, Test Procedures, and performance
				requirements.