[Nhcoll-l] Shelves vs. racking

Tue Aug 17 12:50:33 EDT 2021

Another consideration is the difference between cantilever shelves and racking. The former are only supported on one side, so adding weight to them creates a rotational stress at the point where the horizontal spur meets the vertical support. This can fail well before the nominal maximum loading of either the shelf or the support is reached.
With racking, the shelves are supported on two sides (back and front), so all stresses are simple. In addition, the number of load-bearing points is doubled, so the load on each is halved. If you anticipate heavy loads, increasing the number of vertical elements in a given length of racking can compensate for that.
Finally, racking can be placed on feet that further distribute the load. It’s the best way to go.

Paul Callomon
Collection Manager, Malacology and General Invertebrates
________________________________
Academy of Natural Sciences of Drexel University
1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA
prc44 at drexel.edu<mailto:prc44 at drexel.edu> Tel 215-405-5096 - Fax 215-299-1170

From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> On Behalf Of John E Simmons
Sent: Tuesday, August 17, 2021 11:23 AM
To: Gali Beiner <gali.beiner at mail.huji.ac.il>
Cc: NHCOLL-new <nhcoll-l at mailman.yale.edu>
Subject: Re: [Nhcoll-l] Shelves load capasity

External.
In addition to the excellent advice already offered about shelf material, floor loading, etc., there is also the issue of how weight is distributed on the shelf.

When the weight is more or less evenly distributed (e.g., in boxes of similar shape) shelves may behave differently than when the weight is concentrated on one end or in the middle. We encountered this problem in selecting shelving for the Fluid Collections Research Facility at the University of Kansas back in the 1990s when we discovered that despite the weight capacity rating of the shelves, some shelves bent when loaded with jars of specimens if the weight was not evenly distributed. Therefore, in the specifications for shelving, we specified both a weight capacity (we selected 500 pounds per shelf, based on the maximum potential weight of the jars we could fit on the shelf) and also that the shelves must not flex (bend) more than 1/8 of an inch when fully loaded. We were able to purchase shelves that met these requirements and they worked fine. I have heard stories from other collections that had steel shelves bend under unevenly distributed weight loads.

--John

John E. Simmons
Writer and Museum Consultant
Museologica
and
Associate Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
and
Investigador Asociado, Departamento de Ornitologia
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima

On Tue, Aug 17, 2021 at 11:14 AM Gali Beiner <gali.beiner at mail.huji.ac.il<mailto:gali.beiner at mail.huji.ac.il>> wrote:
Hello Joosep,

Adding to Carrie's notes:

1. The floor carrying capacity is also important. If your shelving is planned for a floor other than the basement, the floor carrying capacity will vary considerably, depnding on the consruction specifics of the building. A consrtuction engineer should be able to give you an estimate of that. In our case, the university construction maintenance personnel guided us re: possibility of setting up this or that type of shelving in specific locations. It wasn't as simple as it sounds because our building wasn't new so we had to change some of our original shelving plans due to estimated floor carrying capacity.

2. Type of shelving matters also in terms of static vs. moving (compactor) shelving. The way the type of shelving interacts with the floor carrying capacity is what you need to know so you can determine the safe maximum load per square meter.

3. Prior to installing new shelving (in our case, compactors in basement floors) I chose several shelves with extra heavy loads in our old collection storage system and actually weighed everything on these shelves to determine real numbers of maximum weight our shelves would be required to carry. We dealt both with wet and dry collections, so the (maximum) weight per shelf in each collection type could vary considerably. You could do the same to determine your own requirements, take 10 shelves or so, weigh their contents and round upward the highest numbers as your minimum weight capacity guideline.

Hope this helps,

Gali

בתאריך יום ג׳, 17 באוג׳ 2021, 17:47, מאת Carrie A. Eaton ‏<carrie at geology.wisc.edu<mailto:carrie at geology.wisc.edu>>:
Hi Joosep,
The load capacity is largely driven by the material from which the shelf is made (steel, I assume?) but a big portion of what controls the shelf’s carrying capacity is the post construction (the uprights that hold the shelf) and how that load is transferred to the floor. You also have to take in account the weight of the shelf itself. So a steel shelf with a 500lb capacity and 100lb of steel decking that makes up the shelf would only hold 400lb of objects. Having just dealt with some difficulties with inadequate load capacities, I would highly encourage you to inquire with the manufacturer and get a good estimate of the shelf’s carrying capacity before putting objects on it. This was also save your back the trouble of having to lift objects multiple times. Best of luck!
Cheers,
Carrie

Carrie Eaton, Museum Curator
UW Geology Museum
1215 West Dayton Street
Madison, WI 53706
608.262.4912
twitter @uwgeologymuseum
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From: Nhcoll-l [mailto:nhcoll-l-bounces at mailman.yale.edu<mailto:nhcoll-l-bounces at mailman.yale.edu>] On Behalf Of Joosep Sarapuu
Sent: Tuesday, August 17, 2021 9:40 AM
To: Joosep Sarapuu <Joosep.Sarapuu at loodusmuuseum.ee<mailto:Joosep.Sarapuu at loodusmuuseum.ee>>; NHCOLL-new <nhcoll-l at mailman.yale.edu<mailto:nhcoll-l at mailman.yale.edu>>
Subject: Re: [Nhcoll-l] Shelves load capasity

Sorry, I forgot to add what collections are on the shelves. We need these shelves for bones and horns. And the other ones are for stuffed animals and for fluid collections.

Sincerely,
Joosep Sarapuu

From: Nhcoll-l [mailto:nhcoll-l-bounces at mailman.yale.edu] On Behalf Of Joosep Sarapuu
Sent: Tuesday, August 17, 2021 5:35 PM
To: NHCOLL-new <nhcoll-l at mailman.yale.edu<mailto:nhcoll-l at mailman.yale.edu>>
Subject: [Nhcoll-l] Shelves load capasity

Dear all,
I think some of you have been already had this situation before.
We are going to have a new shelves for our collection rooms and we would like to know what should be the load capasity for shelves. Our shelves sizes are 100x59cm.
Can somebody give me estimate load capasity for these ones?

Sincerely,
Joosep Sarapuu

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