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PERFORMANCE OF BRACKET-TYPE LIBRARY BOOKSTACKS
During 1998, 15 samples of shelving from eight manufacturers were tested in accordance with The American National Standard for Single Tier Bracket Steel Library Shelving ANSI/NISO Z39.73 1994. The following brief introduction describes the test procedures.
PROVISIONS OF THE STANDARD
The standard is divided into six major sections. Section 1 defines the type of shelving covered by the standard. It states, for example, that the standard covers "single-tier bracket (freestanding) bookstacks consisting of two upright supports columns per modular section with adjustable shelves cantilever-hung on brackets on both sides of the upright."
Section 2 defines the terms used in the standard that apply to this type of shelving. Specifically, it defines such important terms as adder-section, canopy, closed-base, freestanding, end panel or plate, gusset, nominal dimensions, open base, range, section, spreader, and sway brace.
Section 3 defines the test sample. It stipulates that a sample range of two sections from the normal production of the manufacturer is to be used for testing. A section is to consist of a double-faced unit of modular length (usually 3 ft.) with twelve 10-inch (nominal) adjustable shelves, base shelves, uprights, and other parts standard with the particular brand of shelving. Open based shelving is to contain fourteen shelves. The sample range consists of two sections joined together to form a continuous range (see Figure 1). Section uprights may be either 84 or 90 inches tall and must be evenly spaced on modular centers in the range by spreaders. The range itself is to be installed by a representative of the manufacturer or by a competent installer if the manufacturer declines to take responsibility for installation. For purposes of testing, all of the shelving is to be equally spaced vertically on the uprights.
[Figure 1 ILLUSTRATION OMITTED]
Section 4 treats the appearance of the finish. All parts-shelves, brackets, uprights, and supports are examined in order to determine if the shelving finish is smooth and uniform, without runs, wrinkles, grit, or "orange peel" effects or if it shows areas of thinness, exposed substrata, or color separation.
Section 5 treats user-related design characteristics of the shelving. The shelving is to be inspected to ensure that the finished parts are free of burrs and sharp edges. Visually, the magnitude of gaps between abutting shelves or brackets is limited to no more than 3/32 inches. The shelving unit is also inspected to ensure that both empty and fully loaded shelves can be removed and re-hung with no difficulty. As part of the inspection, brackets, hooks, and lugs are checked for alignment with corresponding slots.
Section 6 defines the physical tests to be carried out on the range or its components. Eight major categories of interest are covered. The first three categories deal with the structural characteristics of the shelving, whereas the last five deal with the finish. The eight categories are:
1. Lateral deflection or deviation of the uprights under loads
2. Deflection of shelves under load, i.e., shelf sag
3. Longitudinal deflection of uprights under horizontal pull
4. Gloss of finish
5. Adhesion of finish
6. Resistance of the finish to abrasion
7. Resistance of the finish to acids and chemicals
8. Resistance of the finish to lighted cigarette.
Each of these categories is discussed in detail in the sections which follow.
1. Lateral Deflection of the Uprights Under Load
The first of these categories, lateral deflection or deviation of the uprights under load deals with the sideways movement of the shelving when either one side or both sides of the shelving in a range unit are loaded. The standard states that properly constructed and installed shelving should not lean, sag, or bend excessively when loaded, even when the load is unbalanced. In effect, therefore, this test is intended to evaluate both the stiffness and the strength of the unit.
In carrying out this test, the sample range is first installed and leveled on an appropriate test floor. Some type of measurement device is then installed in order to determine the initial or "zero load" position of an end and center upright with respect to sideways deflection (measurement #1). Dial gauges, Figure 1, provide a convenient means of measuring such deflections, but other devices may be used. The shelves are then loaded as follows.
The shelves on one side of the unit are loaded from the top down with a load of 50 pounds per foot. Thus, for example, the total load on a 3-foot long shelf is 150 pounds. This load is to be uniformly distributed along the length of the shelf in much the same manner that a shelf is loaded by books. Several types of loads such as steel weights or bags of lead shot may be used. Concrete bricks, which on average weigh 5 pounds apiece and measure 2 inches thick by 4 inches wide by 8 inches long may also be used. The range shown in Figure 1 illustrates the use of such weights. The sidesway deflection of the tops of the uprights under the action of these loads is then noted and recorded. The location of the top of the end and center uprights is then noted and recorded (measurement #2).
The shelves on the second side of the sample range are then loaded in the same manner as the first side and the deflection of the tops of the uprights is noted and recorded (measurement #3).
All of the loads are removed from the shelf and the deflection of the tops of the uprights is noted and recorded (measurement #4).
Acceptance levels for deflection are as follows. Under the action of the loads on one side of the range only (measurement #2) deflections shall not exceed 64/64 inch (1 inch) Under the action of loads on both sides of the range, deflections shall not exceed 20/64 inches (5/16 inches). Finally, residual deflections of the unloaded range shall not exceed 8/64 inch (1/8 inch).
2. Deflection of Shelves Under Load (Shelf Sag)
The second category, deflection of shelves under load, deals with the unsightly condition that can arise if the shelves themselves deflect excessively under load as well as the unsafe structural condition that arises. In this test, five shelves are selected at random and installed on the uprights. The deflection profiles of the front edge of the unloaded shelves are then determined (measurement #1).
Ordinarily, shelf deflection is maximum at the midpoint along the length of the shelf; thus, measurements are normally taken at this point. A dial gauge used in connection with a simple deflection jig constructed out of a 1-inch square steel bar and two short lengths of steel angle, Figure 2a, provide a convenient method of measuring such deflections, but other methods may be used. A lineal load of 50 pounds per foot is then applied uniformly along the length of the shelf, Figure 2b. The load is maintained on the shelf for 24 hours, at the end of this time, shelf deflection is again measured and recorded (measurement #2). The shelves are then unloaded and allowed to sit in the unloaded condition for 6 hours. At the end of this time, the residual deflection is measured (measurement #3), Figure 2a.
[Figure 2 ILLUSTRATION OMITTED]
Acceptance levels for shelf deflection are as follows. Initial deflection before loading (measurement #1) is to be less than 1/64 inch. Deflection under load, measurement 2, is not to exceed 12/64 inches. Finally, residual deflection after the load is removed (measurement #3) is not to exceed 1/64 inch.
3. Longitudinal Deflection of Uprights Under Horizontal Pull
The third category, longitudinal deflection of uprights under horizontal pull, deals with the deflection of the range along its length under the action of forces applied along the longitudinal axis of the range, Figure 3. In effect, therefore, this test measures both the stiffness of the range and its ability to resist longitudinal loadings. The test is carried out on a two-section double-faced range with shelves installed. Each of the four base shelves, or the bottom four adjustable shelves if base shelves are lacking, is then loaded with 200 pounds. These loads are applied uniformly along the lengths of the shelves. A 100-pound force is then applied to an upright in a horizontal direction parallel to the longitudinal axis of the range at a point 48 inches above the floor. After the load has been applied for 10 minutes, deflection of the upright at a point 48 inches above the floor is measured and recorded.
[Figure 3 ILLUSTRATION OMITTED]
The acceptance level is as follows. Deflection of the upright (at a point 48 inches above the floor) is not to exceed 16/64 inches.
4. Gloss of the Finish
The fourth category, gloss of finish, deals with the appearance of the finish. In general, properly finished shelves should have a uniform, overall pleasing gloss, neither so shiny as to be a distraction, nor too dull.
Gloss is determined by a 60 degree gloss meter according to ASTM Method 0523-53T. (A "60 degree gloss meter" is a specific piece of equipment that is available from scientific equipment houses.) In practice, the meter, which measures about 4 inches wide by 12 inches long, is simply set on the top of a shelf. A push-button switch is then pushed, which activates the unit. The gloss reading then appears on the read-out screen located on the top of the unit. Two random readings are taken on each of five randomly selected shelves. The average of each set of two readings is reported.
The acceptance level is as follows. Average gloss values shall not exceed 60 nor be less than 30.
5. Adhesion of the Finish
The fifth category, adhesion of finish, deals with the bonding of the finish to the metal substrate. Two tests are included in this category, namely, a bending test and an impact test.
Bending Test. In the bending test, a metal coupon that measures about 4 inches wide by 8 inches long is cut from a shelf and bent double around a 1/4-inch diameter mandrel, Figure 4. Two coupons are tested. One is to be cut from a shelf with its major axis parallel to the longitudinal axis of the shelf, whereas the other is to be cut with its major axis perpendicular to that of the shelf. Tests are to be carried out with the finish side up.
[Figure 4 ILLUSTRATION OMITTED]
Acceptance levels are as follows. No separation of the finish from the substrate is permitted except for small cracks at the edges of the panels that extend no more than 1/4 inch.
Impact Test. In the impact test, a 2-inch diameter steel ball is allowed to free-fall 10.5 inches onto the surface of a sample coupon cut from a shelf. This test may be carried out with the equipment shown in Figures 5a and 5b, but other equipment that holds and releases the ball at the pre-determined height may be used. A 1-1/4-inch diameter hole is located in the support table immediately below the sample coupon. The center of this hole coincides with the point of impact of the steel ball. Two tests are carried out. One test is carried out on a coupon with the finish side up; a second test is carried out on another coupon with the finish side down.
[Figure 5 ILLUSTRATION OMITTED]
Acceptance levels are as follows. In general, there should be no adverse effects. In particular, cracks, hairline cracks, or chipping of the impact area are noted.
6. Resistance of the Finish to Abrasion
The sixth category, resistance of the finish to abrasion, deals with the ability of the finish to resist the continual sliding of books and other materials over its surface.
Tests are carried out on three shelves randomly selected from each range. Film thickness is measured at six randomly selected points on each shelf, three of which are to be located on the top of the shelf and three on the front edge. The falling sand abrasion test, ASTM Method D968-51, is then carried out at the three locations on each shelf that have the thinnest film thickness. This test is carried out as is shown diagrammatically in Figure 6. In general, sand (of a prescribed size) is allowed to fall onto the surface of a shelf that is set at an angle of 45 degrees to the path of the sand. The average of the number of liters required to expose a 3/16-inch diameter spot of substrate at the three test points is computed and recorded.
[Figure 6 ILLUSTRATION OMITTED]
The acceptance level is as follows. The amount of sand required to expose the substrate must be equal to or exceed 30 liters.
7. Resistance of the Finish to Acids and Chemicals
The seventh category, resistance of the finish to acids and chemicals, deals with the ability of the finish to resist the effects of liquids that may be encountered in normal use or in cleaning. Five liquids are included in the test, namely, a 95% solution of isopropyl alcohol, a 10% solution of acetic acid, machine oil, undiluted household ammonia, and a 10% solution of lye. In practice, five 1.5-inch diameter pieces of filter paper are placed at five randomly selected positions on the finish side of a shelf. One of the five pieces of filter paper is then soaked with alcohol, the second with acetic acid, the third with machine oil, the fourth with ammonia, and the fifth with lye. Each of the five pieces of filter paper is covered with a watch glass to prevent evaporation. The alcohol-, acetic acid-, machine oil-, and ammonia-soaked pieces of paper are allowed to remain in place for 30 minutes, whereas the lye-soaked piece of paper is allowed to remain in place for only 15 minutes. Once the soak times have been completed, the filter paper is removed, and the surfaces are thoroughly rinsed with water and wiped dry. Note that the start time for the lye-soaked piece may be delayed 15 minutes so that soak times are completed together. Any evidence of discoloration or softening of the finish is noted along with any other blemishes that may arise.
The acceptance level is as follows. No detectable adverse effects are allowed.
8. Resistance of the Finish to a Lighted Cigarette
The eighth category, resistance of the finish to a lighted cigarette, was intended to determine the ability of the finish to resist the abuse that occurs as a result of what was at one time a potentially common occurrence. The acceptance level is as follows. No detectable adverse effects are allowed.
SUMMARY OF LABORATORY FINDINGS
Physical Characteristics Determined by Testing
1. Lateral Deflection or Deviation of the Uprights under Loads: All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
2. Deflection of Shelves under Load (Shelf Sag): All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
3. Longitudinal Deflection of Uprights under Horizontal Pull: All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
4. Gloss of Finish: All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
5a. Adhesion of Finish-Bending: Except for the Southern Metal sample, all other samples tested were in compliance with ANSI/NISO Z39.73-1994.
5b. Adhesion of Finish-Impact: All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
6. Resistance of the Finish to Abrasion: All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
7. Resistance of the Finish to Acids and Chemicals: All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
8. Resistance of the Finish to a Lighted Cigarette: All 15 samples tested were in compliance with ANSI/NISO Z39.73-1994.
BC INVENTAR, INC.
Steel Cantilever Shelving System 90
Manufactured by: BC Inventar A/S Dalbaekvej 1 DK 6670 - Holsted Denmark BC Inventar, Inc. 4617 Montrose Boulevard, Suite C170 Houston, Texas 77006 (713) 522-9715; fax (713) 522-8698 www.bci-usa.com
Established as a service organization for the Danish Royal Libraries in 1939, BC Inventar (BCI) started producing its own line of library furniture in 1967. Now, specializing in the development and production of systems, BCI offers a full range of furniture and shelving to an international market. BCI is now a subsidiary of the ITH concern. In addition to two lines of cantilever steel shelving, BCI produces two wood and steel shelving systems and two 4-post shelving lines. All six shelving systems offer various integrated lighting features, signage, and many standard components. At present, BCI offers 18 standard epoxy powder coat paint colors plus custom colors utilizing NCS (Natural Color System).
BCI has a 150,000+ square foot manufacturing facility staffed with over 130 employees in Holsted, Denmark. The design office headquarters are located in Copenhagen. Staff designers are also available at individual office locations. International design and sales operations, besides those in Denmark and the U.S. (Houston), are located in France, Norway, and Spain.
The shelving systems submitted for testing were basic units and did not include additional structural members such as end panels, sway bracing, angled gussets, etc. Several end panel options are, however, available.
Installations in the United States include: Bergen Community College Library (Bergen, NJ); City of College Station Public Library (College Station, TX); Cottonwood Public Library (Cottonwood, AZ); Muscle Shoals Public Library (Muscle Shoals, AL); and National Defense University Law Library (Washington, DC). International installations include: Arendal Peoples Library (Norway); Mukogawa Library (Japan); Pharmacist Association (Barcelona, Spain); University Library (Nantes, France).
One range of two shelving sections nominally measuring 90" high x 36" wide x 9"/9" deep, and included (1) starter frame with two double-sided uprights and three horizontal clip-in crossbars, (1) add-on frame with one double-sided upright and three horizontal clip-in crossbars, (14) shelves with 2" high back edge and applicable brackets per section, and (2) closed base plates per section. Each upright offers 1" component adjustability, with an opened or closed base solution.
Individual sections consist of rectangular slotted inverted T-shaped uprights with top, bottom, and center spreaders. The spreaders have hooks in their ends which fit into corresponding slots in the uprights. Therefore, this unit can be assembled without bolting the rails to the uprights. Each upright is provided with two 2-inch diameter leveling guides with threaded bolts which allow adjustment at any time.
All base and adjustable shelves are of exactly the same form and size. The shelves offer a 1-7/8 inch high integrated back edge and are placed on 6 inch high brackets. The brackets include three hooks for connection to the upright column. Two of the hooks are located towards the top of the bracket; the third hook is located at the bottom. Double-faced brackets are equipped at the center upright of the unit. A kick plate is equipped to close the space beneath each base shelf.
The test sample had neither end panels, sway bracing, gussets, nor canopy tops; however, all are offered by the company.
Shelf Dimensions: Length: 35-1/4 inch; Depth: 9 inch Formed edge: Front: 1 x 1/4 inch; Rear: 1-7/8 x 1/8 inch Thickness of steel: 0.034 inch (#21 gauge) Space between back edges of shelves: 3-1/4 inch Bracket Dimensions: Height: 5-7/8 inch; Depth: 8-7/8 inch Number of hooks: 3; Number of lugs: 0 Radius of rolled edges: 1/2 inch Thickness of steel: 0.049 inch (#18 gauge) Upright Dimensions: Width: 3-1/8 inch; Depth: 13/16 inch; Height: 89 inch Slots: Frequency: 1 inch on centers; Size: 3/16 x 11/16 inch Height of top slot from top of uprights: 0 inch Shape and positioning pattern: Rectangular slots Minimum spacing between shelves: 4-7/8 inch Thickness of steel: 0.071 inch (#14 gauge) Construction: Fabricated from rectangular tubing Leveling Method: Leveling bolts with plastic caps installed on the ends of each foot Top Spreader Dimensions: Length: 34-1/4 inch; Depth: 4 inch; Thickness: 1-3/4 inch Covers top slot of upright? No Thickness of steel: 0.056 inch (#16 gauge) Bottom Spreader Dimensions: Length: 34-1/4 inch; Depth: 4 inch; Thickness: 1-3/4 inch Thickness of steel: 0.056 inch (#16 gauge) Center Spreader Position: Attached at the heights of 38-1/2 inches from floor Dimensions: Length: 34-1/4 inch; Depth: 4 inch; Thickness: 1-3/4 inch Thickness of steel: 0.056 inch (#16 gauge) Base Shelf Dimensions: Length: 35-1/4 inch; Depth: 9 inch Formed edge: Front: 1 x 1/4 inch; Rear: 1-7/8 x 1/8 inch Construction method: Shelf is of two-piece construction Thickness of steel: 0.034 inch (#20 gauge) Sway Braces Description: None End Panel Description: None Canopy Tops Description: None Gusset Plates Description: None
The tubular construction of the uprights contributes to the strength and stiffness of the unit. In addition, the weld between the upright and foot bar provides high resistance to lateral deflection resulting from shelf loads. The lateral deflection of the center upright was somewhat larger than that of the end upright, but it still meets the test specification. Overall, results indicate that the unit has high lateral strength and stiffness.
The unit was tested with levelers but without end panels or any other reinforcement. Use of three spreaders instead of two seemingly contributes to the strength and rigidity of the unit in lengthwise direction.
Condition of Finish Findings: The shelving satisfied the test specification. Hazards to Books or People Findings: There are no burrs or sharp edges shelf brackets. None of the gaps between the ends of the shelves and the shelf brackets exceeded 3/32 inches. Ease of Changing Unloaded Shelves Findings: The shelves are easy …