1、Ergonomic Guidelines for Small Lot Delivery OperationsSAE/USCAR-42 March 2015ISBN: 978-0-7680-8188-6 TABLE OF CONTENTS 1.0 Scope 2 2.0 Referenced Documents . 2 3.0 General 2 4.0 Material Location . 3 a. Determining Shelf Height 4 b. Rack Design Features and Material Placement: Clearances . 6 c. Othe
2、r Rack Design Features 7 d. Features to Make Container Extraction Easier . 7 e. Delivery Points 8 f. Aisle ways at Load and Delivery Points 8 5.0 Load Weight and Size . 8 a. Container Size Limitations 8 b. Accommodating Over-Sized Containers. 9 c. Coupling and Handholds 10 d. Returnable and Non-retu
3、rnable (Disposable/Expendable) Containers 10 6.0 Equipment Design and Configuration . 11 a. Tow Tractor Design . 11 b. Standing vs. Seated Tow Tractors 11 c. Issues With Stand-up Tuggers . 11 d. Trailer Design 11 7.0 Safe and Proper Material Handling Techniques . 12 8.0 Handling/Delivery Frequency 1
4、3 a. Procedure for Using the Matrix Guidelines . 13 b. Adjustments to the Guidelines 16 c. Notes on Recovery Time 16 d. Limits on Applicability 16 e. Consideration of Marketplace Attendants/Material Receivers 17 f. Activity and Element Composition and Times Use of Standard Time Data to Plan Marketpl
5、ace jobs 17 Appendix A. References . 18 Appendix B. Expanded NIOSH CLI Matrices 20 Appendix C. Conducting a Specific Analysis of a Marketplace Route 21 Appendix D. Interpolation of CLIS from Intermediate Vertical Percentages from the Matrices 24 SAE/USCAR-42 Issued 2015-03 Ergonomic Guidelines for S
6、mall Lot Delivery Operations _ The research data, analysis, conclusion, opinions and other contents of this document are solely the product of the authors. Neither the SAE International (SAE) nor the United States Council for Automotive Research (USCAR) certifies the compliance of any products with
7、the requirements of nor makes any representations as to the accuracy of the contents of this document nor to its applicability for purpose. It is the sole responsibility of the user of this document to determine whether or not it is applicable for their purposes. Copyright 2015 USCAR Printed in U.S.
8、A. All rights reserved. QUESTIONS REGARDING THIS DOCUMENT: (248) 273-2470 FAX (248) 273-2494 TO PLACE A DOCUMENT ORDER: (724) 776-4970 FAX (724) 776-0790 SAE/USCAR-42 Issued 2015-03 ERGONOMIC GUIDELINES FOR SMALL LOT DELIVERY OPERATIONS - 2 - 1.0 SCOPE This document describes the design, assessment
9、methods and physical requirements associated with material handling systems. This would include, but not limited to manual dollies, small lot systems and kitting. All possible designs and applications could not be anticipated in creating these guidelines. Where there are questions of adherence to th
10、is document, such as use of an “off-the shelf” design, always consult the responsible Ergonomics Department. 2.0 REFERENCED DOCUMENTS See Appendix A for references broken out by specific area. Guidelines published by Ford Motor Company, General Motors LTD and the Automotive Industry Action Group (AI
11、AG) are the key sources for information and methods discussed in this guideline. The AIAG OHS-5: Ergonomics Guidelines for Small Lot Delivery Systems was created with the participation of General Motors, Ford, Chrysler, Toyota USA, NIOSH, Liberty Mutual Research Institute for Safety and the UAW amon
12、g other participants. 3.0 GENERAL The approach taken in this guideline is comprehensive and does not focus solely on a single aspect of the task such as the maximum weight handled or the number of cartons or containers delivered per route. The following general areas will be addressed in this bookle
13、t: Material locations (height, reach): Load (container) weight and size Equipment (racks, tow tractors, trailers) design and configuration; Handling frequency (number of items handled per unit time or route:; Activity ad element composition and times. Material pull systems, lean material systems, Ka
14、nban, Electronic Pull Systems (EPS), PPS and Just-In-Time are different terms for the same basic system. This system uses strategies for the reduction of inventory and the delivery of material to the production line as it is needed. Materials are delivered in small lots and on a relatively frequent
15、basis to the line in pull systems. Handling of material in totes in the pull system is performed manually by workers. Pull systems typically have the following features: the jobs typically have a high degree of variation in the size, weight and frequency of items handled; the jobs are repetitive but
16、 not cyclical, i.e., the same lifts, weights and carry distances are not repeated at exactly the same intervals; the jobs are made up of composite activities (lifting, lowering, and carrying) of which the most limiting condition ergonomically may not be clear; and, there are differences in pull syst
17、em strategies (i.e., coupled vs. decoupled systems) and in different delivery schedules, etc. Terminology and Concepts Various terms have been used to describe small lot operations such as: “material mall,” “material supermarket,”, “central material area” and “decanted marketplace. They all refer to
18、 kanban-based small lot delivery systems. All three terms mean essentially the same thing - material pull systems with small lot delivery by means of tow tractors. “Timed Route” most all small lot delivery routes are timed in some way such as the provision for a route every hour, etc. In Body Shop a
19、pplications a “timed route” may refer to the delivery of subassemblies to the line at regular time intervals. Such deliveries are usually not small lot but subassemblies or parts in racks. “Electronic Pull System” is a wireless system that is used in place of kanban pull cards for small lot delivery
20、 systems in several global locations. Coupled Operations - refers to the system where the route driver both loads the tow tractor/trailer(s) in the CMA and makes the deliveries to the line. SAE/USCAR-42 Issued 2015-03 ERGONOMIC GUIDELINES FOR SMALL LOT DELIVERY OPERATIONS - 3 - Decoupled Operations
21、- refers to the system where the tow tractor/trailer(s) are loaded by an attendant in the CMA. The route driver in a decoupled system only makes deliveries on-line and does not load the tow tractor/trailer(s). Some plants use CMA operations that are located offsite from the plant. The trailers are l
22、oaded by third parties or contractors and brought into the plant for delivery. In this document the term “marketplace” will be used to refer to small lot marshaling areas and small lot operations in general. General Description of Route Driver Job Responsibilities in Marketplace Operations In the co
23、upled Marketplace, a route driver is responsible for picking totes and boxes from the roller racks and loading them onto a trailer or dolly. Once all of the required stock has been collected, the route driver delivers the totes and boxes to lineside racks or platforms. While making the deliveries, t
24、he route drivers are required to pick up the empty totes and boxes and place them on the trailer. The route driver returns to the marketplace area once the totes and boxes have been delivered and deposits the empty containers onto the dunnage return area. The responsibilities of the route driver inv
25、olve a variety of manual material handling tasks. As a result, the work area layout of the route driver should be evaluated to determine if it complies with the ergonomic guidelines that have been created. Following the work area and process recommendations will help to decrease the exposure to risk
26、 factors that have been associated with manual material handling injuries. 4.0 Material Location Note: the term “rack” is taken to refer to the storage unit itself while “shelf” refers to a level on that unit that is used to hold material. See the following pictures of typical roller racks employed
27、in Marketplace operations below. The unload (pick) end of the roller rack in a Marketplace. SAE/USCAR-42 Issued 2015-03 ERGONOMIC GUIDELINES FOR SMALL LOT DELIVERY OPERATIONS - 4 - The loading end of the roller rack in the Marketplace. In this picture, there is an extra level of storage for extra in
28、ventory, and this stock is accessed using motorized lifting equipment. For the picking of material in the marketplace, utilize roller racks (shelves have roller units) instead of flat racks for most sizes of containers. Recommendations for shelf heights are based on the height of the hands as contai
29、ners or cartons are grasped and lifted out of the rack. Recommended ranges are given in Figure 1. Determining Shelf Height Consider the heights of containers when setting shelf heights. Most returnable containers and totes will have handles that place the hands 200 mm (8 in) or more above shelf heig
30、ht when grasped. As such, the shelf may be lower than the recommended range with the hands maintained within it. Disposable (cardboard) cartons usually lack handles or handholds of any sort and are lifted either with the hands at opposite corners or along the lower edges. Marketplace workers vary in
31、 their techniques although handling by gripping the lower edges is more common. In such a case hand height would equal shelf height. If the carton is grasped at opposite corners, one-half the height of the carton may be taken as the hand height; usually in the range of 100 to 200 mm (4 to 8 in) abov
32、e the shelf height. The limits given in Figure 1 are based upon anthropometric, NIOSH 1991 Lift equation parameters and psychophysical lifting limits. If only lowers as opposed to lifts are performed from that height, the recommended weight limits may increase and demand a separate analysis. SAE/USC
33、AR-42 Issued 2015-03 ERGONOMIC GUIDELINES FOR SMALL LOT DELIVERY OPERATIONS - 5 - Figure 1 Recommended Range for Vertical Hand Height for lifts of loaded containers Maximum Forward Reach 460 mm (18 in.) Over 1780 mm/70 inches - not recommended for loaded containers (See Note 1) Should generally be r
34、eserved for 1400+ to 1780 mm lighter weights, 7 kg (15 lb.) and under (55+ to 70 in) (see text for notes) and 10% or less of lifts. Prime lifting vertical height region 635+ to 1400 mm (25+ to 55 in) 80 to 85 % of lifts should be within this range Minimize lifting from/to this vertical 250 mm to 635
35、 mm (See Note 3) Height range - no more than (10 + to 25 in) 5 - 10% of lifts at most should originate or end within this range No lifting to/from this range Floor level to 250 mm (10 in) Floor level Note 1 Above 1780 mm/70 in may be used for empty containers that are 635 to 1400 mm, o 1400 to 1780
36、mm for 60-70 70-80 80-90 90-100 100-110 110-120 120-130 130-140 9 kg (20 lb) 1.10 1.13 1.17 1.22 1.26 1.31 1.36 1.40 9 - 11 (20-25 lb) 1.32 1.34 1.38 1.44 1.48 1.52 1.57 1.63 11 - 13 (25-28 lb) 1.44 1.48 1.52 1.57 1.61 1.66 1.71 1.75 13 14.5 (28-32 lb) 1.53 1.56 1.60 1.65 1.70 1.74 1.79 1.85 14.5 -
37、16 (32-35 lb) 1.75 1.78 1.82 1.87 1.92 1.96 2.01 2.07 16 17.5 (35-38 lb) 1.87 1.92 1.96 2.0 2.04 2.09 2.15 2.19 17.5 - 18 (38-40 lb) 1.96 1.99 2.03 2.09 2.14 2.18 2.23 2.28 -50% or more lifts outside recommended range Number of lifts per hour Weighted average of container weights kg (lb) 60-70 70-80
38、 80-90 90-100 100-110 110-120 120-130 130-140 9 kg (20 lb) 1.24 1.28 1.33 1.38 1.44 1.46 1.49 1.55 9 - 11 (20-25 lb) 1.49 1.53 1.56 1.64 1.69 1.74 1.80 1.80 11 - 13 (25-28 lb) 1.63 1.67 1.73 1.78 1.84 1.86 1.89 1.95 13 14.5 (28-32 lb) 1.83 1.87 1.92 1.98 2.04 2.06 2.09 2.15 14.5 - 16 (32-35 lb) 1.97
39、 2.02 2.07 2.12 2.19 2.21 2.24 2.31 16 17.5 (35-38 lb) 2.12 2.17 2.22 2.27 2.33 2.36 2.39 2.46 17.5 - 18 (38-40 lb) 2.22 2.26 2.32 2.37 2.43 2.46 2.49 2.56 Please see Appendix B for an expanded matrix for number of lifts that are under 60 per hour or over 140 per hour. SAE/USCAR-42 Issued 2015-03 ER
40、GONOMIC GUIDELINES FOR SMALL LOT DELIVERY OPERATIONS - 16 - Adjustments to the Guidelines Some conditions may result in conditions that are more stressful than indicated by the matrix CLI. Given below are specific conditions and advice on how the matrix values can be modified or supplemented. Specif
41、ic analyses (see Appendix B) can also capture and assess the particular conditions. o Long horizontal distances The horizontal distance of the load from the material handlers body is the most crucial of the dimensional measurements in terms of its impact on the CLI. It is also the most difficult to
42、measure or estimate in many cases. If the horizontal distance routinely exceeds 400 mm (16 in) for 40% or more of the lifts due to large container size, material location and personal technique, then modification of the CLI values in the Matrices will be needed. If, on the analysis of a particular r
43、oute, the horizontal distances average over 400 mm (16 in) , then the CLI values should be increased by 25% (i.e., multiply the value by 1.25 with the same CLI interpretation). Long horizontal distances should be a priority for engineering change. o Over-sized Containers The CLI matrix may be modifi
44、ed in the same way for over-sized containers as for excessive horizontal distances. If over-sized containers are between 30-50% of the weighted average lifts on a route, then multiple the CLI value by 1.15. If the weighted average of lifts of oversized containers exceeds 50%, then multiple the CLI b
45、y 1.25. Also, if the empty over-sized returnable containers generally require handling with two hands, then include them in the count of containers handled if they weigh 2 kg (5 lb) or more. o Workdays Exceeding 8-9 hours If the work day exceeds an eight to nine hour day, then the frequencies may ne
46、ed to be discounted. An energy expenditure prediction analysis (based upon Gargs equations) may be used to determine the metabolic demands of the jobs and then an appropriate discount in the limits suitable for the length of the workday can be figured. For example, if an eight-hour energy expenditur
47、e rate of 5 kcal/min is used, a discounted limit based upon a 10-hour workday may be 4.2 kcal/min. Routes exceeding the revised limit would require intervention. Notes on Recovery Time Standard time data systems used to plan material handling jobs include time allowances for all activities. They mak
48、e a number of assumptions about walk distances, lifting conditions, etc. These systems will have a time allowance for most activities and as such has a built-in degree of recovery time. The standard time analysts should make sure that all of the duties of the route drivers, marketplace attendants, e
49、tc. are completely and accurately described in the standard time planning. Limits on Applicability The matrix guidelines were formulated to address marketplace jobs. It is assumed that the routes will involve a marked degree of variety in items handled and in multiple locations delivered to. The guidelines,
