Difference between revisions of "Shelving Units"
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| + | ==Types== | ||
There are 4 main types of shelving rack used by diyers: | There are 4 main types of shelving rack used by diyers: | ||
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Heavy duty angle iron shelving units, eg Dexion | Heavy duty angle iron shelving units, eg Dexion | ||
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* industrial price tag | * industrial price tag | ||
* need bracing to be safe | * need bracing to be safe | ||
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Low cost angle iron steel shelving | Low cost angle iron steel shelving | ||
* medium duty | * medium duty | ||
* need bracing and stabilising to be safe | * need bracing and stabilising to be safe | ||
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Wooden shelving units, usually home made | Wooden shelving units, usually home made | ||
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* can be made any strength | * can be made any strength | ||
* economical | * economical | ||
| + | |||
Moulded plastic shelving units | Moulded plastic shelving units | ||
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A shelf should be fitted at ground level to create a rigid box structure for the legs, and to spread the load on the floor. | A shelf should be fitted at ground level to create a rigid box structure for the legs, and to spread the load on the floor. | ||
| + | |||
| + | Cutting uprights is best done with an angle grinder. | ||
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| − | ====Shelf Materials==== | + | ====[[Sheet Materials|Shelf Materials]]==== |
| − | 12mm chipboard shelves are adequate for most household loads, but can sag in time. 18mm chip is better for larger units and heavier loads. Chipboard needs to sit on a supporting rail on all 4 sides, and additional front to back supports are recommended. Chipboard has no water resistance and is thus not the best choice for outbuildings. | + | '''12mm chipboard''' shelves are adequate for most household loads, but can sag in time. '''18mm chip''' is better for larger units and heavier loads. Chipboard needs to sit on a supporting rail on all 4 sides, and additional front to back supports are recommended. Chipboard has no water resistance and is thus not the best choice for outbuildings. |
| − | WBP ply has much better water resistance and is much tougher than chip. | + | '''WBP ply''' has much better water resistance and is much tougher than chip. '''OSB''' is a modern alternative to ply, with similar characteristics. |
| − | Real wood shelves look nicest indoors, and are stronger than chipboard. It is wise to use sheet wood made from lots of strips glued together with grain curvature in alternating directions. This looks better than planks and is much more resistant to cupping. It is sold as pineboard. | + | '''Real wood''' shelves look nicest indoors, and are stronger than chipboard. It is wise to use sheet wood made from lots of strips glued together with grain curvature in alternating directions. This looks better than planks and is much more resistant to cupping. It is sold as '''pineboard'''. |
| − | Melamine/formica is another option, wipes clean but the same strength as 12mm chip, and edges and corners often deteriorate in time. | + | '''Melamine/formica''' is another option, wipes clean but the same strength as 12mm chip, and edges and corners often deteriorate in time. |
| − | Shelf sheets need cutouts made at each corner to sit on the wooden framework. It is quicker to make a template and use this to cut the shelves, but check the template fits all positions first, often it won't. | + | Shelf sheets need cutouts made at each corner to sit on the wooden framework. It is quicker to make a template from paper and use this to cut the shelves, but check the template fits all positions first, often it won't. |
==Plastic shelving racks== | ==Plastic shelving racks== | ||
| − | |||
Moulded plastic shelving units have one major advantage: great ease and speed of assembly. They are also impervious to damp, which can be a real advantage in an outbuilding. | Moulded plastic shelving units have one major advantage: great ease and speed of assembly. They are also impervious to damp, which can be a real advantage in an outbuilding. | ||
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==Bamboo & Willow== | ==Bamboo & Willow== | ||
| − | Shelving units are occasionally seen made from bamboo and similar materials, often with woven fibre shelves. These units are only suitable for lightweight uses. | + | Shelving units are occasionally seen made from bamboo and similar materials, often with woven fibre shelves. These units are only suitable for very lightweight uses. |
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Many racks are supplied without adequate bracing, and a child (or adult) crashing into one could cause it to fold over sideways, crushing anyone underneath it or caught between its shelves. Due to the lever effect the forces involed in such collapses are often sufficient to crush bones or kill. Metal shelving systems are the worst offenders in this respect. | Many racks are supplied without adequate bracing, and a child (or adult) crashing into one could cause it to fold over sideways, crushing anyone underneath it or caught between its shelves. Due to the lever effect the forces involed in such collapses are often sufficient to crush bones or kill. Metal shelving systems are the worst offenders in this respect. | ||
| − | To be safe, '''wooden''' units must be non-topplable. This is easily achieved with bracing on 3 sides or fixing to a wall. Very small amounts of joint movement are acceptable since movement does not undo the fixings. | + | To be safe, '''wooden''' units must be non-topplable. This is easily achieved with bracing on 3 sides or fixing to a wall. Very small amounts of joint movement are acceptable since movement does not undo the fixings. |
'''Metal''' systems are different in this respect, and any joint movement at all progressively undoes the bolts, causing units to become precarious. Metal systems therefore require sufficient bracing to prevent any joint movement at all. | '''Metal''' systems are different in this respect, and any joint movement at all progressively undoes the bolts, causing units to become precarious. Metal systems therefore require sufficient bracing to prevent any joint movement at all. | ||
| − | Heavyweight units can achieve this with bracing on 3 sides, and with shallower systems fixing to a wall. | + | Heavyweight units can achieve this with bracing on 3 sides, and with shallower systems by fixing to a wall. |
Lighter systems also need bracing on 3 sides, but are typically too shallow to be safe without fixing to either a wall or to other shelving units to make a larger rigid structure. | Lighter systems also need bracing on 3 sides, but are typically too shallow to be safe without fixing to either a wall or to other shelving units to make a larger rigid structure. | ||
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===Torque=== | ===Torque=== | ||
| − | Doing up metal unit fixing bolts with pliers does not give a safe structure. | + | Doing up metal unit fixing bolts with pliers does not give a safe structure. Use a socket or spanner to obtain sufficient torque. |
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Racks without sufficient bracing (on 3 sides) can loosen quickly. In the worst cases an unbraced rack can loosen to the point of collapse in a day or two. | Racks without sufficient bracing (on 3 sides) can loosen quickly. In the worst cases an unbraced rack can loosen to the point of collapse in a day or two. | ||
| + | |||
| + | |||
| + | ==See Also== | ||
| + | [[Sheet Materials]] | ||
| + | |||
| + | [[Shelves]] | ||
Revision as of 15:11, 1 April 2007
Shelving Racks or Shelving Units are multitiered shelving structures, usually free standing. These can be very efficient storage options, but safety is a common problem.
Types
There are 4 main types of shelving rack used by diyers:
Heavy duty angle iron shelving units, eg Dexion
- industrial duty
- industrial looks
- industrial price tag
- need bracing to be safe
Low cost angle iron steel shelving
- medium duty
- need bracing and stabilising to be safe
Wooden shelving units, usually home made
- can be made any shape or size
- can be made any strength
- economical
Moulded plastic shelving units
- extremely quick & easy assembly
- medium duty
Heavy duty angle iron units
These are the big daddy of shelving units. Industrial duty, industrial looks and industrial prices. The only practical option for heavy storage. They consist of holed angle iron uprights with sheet metal shelves, and either angle iron or wood bracing.
Dexion is the best known brand, and heavy duty angle iron shelving is now widely known as Dexion, regardless of brand.
Usually grey painted (commonly lead paint), but very old units may be dark green.
Effective bracing is necessary for safety. Without it these systems can kill.
Units mostly sold as 3' wide bays in a choice of depths and height. 12" 18" and 24" are common depths, with other sizes also in use.
There are a number of different brands and hole patterns, and different systems do not generally fit together satisfactorily. Bodge togethers are generally possible, but not ideal, with shelves often being not exactly horizontal and not so well supported.
1" M6 roofing bolts are the usual choice for assembly.
A shelf should be fitted at ground level to create a rigid box structure for the legs, and to spread the load on the floor.
Cutting uprights is best done with an angle grinder.
Lightweight angle iron shelf racks
A low cost version of dexion, these lighter shelving systems are available from high street stores such as Argos. Strong enough for household storage if stabilised and braced, but too often these units are used with neither, and in such condition are unsafe.
More than one kit can be used to make a taller unit with more shelves.
A shelf should always be fitted at ground level. Omission leaves such units unsafe due to inadequate leg rigidity. If that leaves you one shelf short, a wooden square frame can replace this bottom shelf if necessary.
Wooden shelving racks
An aternative to dexion & lightweight angle iron shelving is wooden shelving racks. The big advantage of these is flexibility, they can be whatever size and shape you like. They therefore fit spaces perfectly, which is usually not true of metal shelving.
Appearance is much better than metal units. If desired, uprights can be routed, shelves profiled, and bracing made decorative.
They may be finished wih varnish or wax for indoor use. Paint is better avoided as scratching is likely. 2"x2" uprights give a lean shelf rack system suitable for typical household loads if well braced and well jointed. Well jointed means metal reinforced joints, with a minimum of 2 screws into the upright and 1 into the shelf. 2x4 gives a higher strength system.
Free units may be made from assorted scrap for storage shed use. Don't be tempted to use non-flush doors as shelves, the non-flat surface is impractical.
Shelf Materials
12mm chipboard shelves are adequate for most household loads, but can sag in time. 18mm chip is better for larger units and heavier loads. Chipboard needs to sit on a supporting rail on all 4 sides, and additional front to back supports are recommended. Chipboard has no water resistance and is thus not the best choice for outbuildings.
WBP ply has much better water resistance and is much tougher than chip. OSB is a modern alternative to ply, with similar characteristics.
Real wood shelves look nicest indoors, and are stronger than chipboard. It is wise to use sheet wood made from lots of strips glued together with grain curvature in alternating directions. This looks better than planks and is much more resistant to cupping. It is sold as pineboard.
Melamine/formica is another option, wipes clean but the same strength as 12mm chip, and edges and corners often deteriorate in time.
Shelf sheets need cutouts made at each corner to sit on the wooden framework. It is quicker to make a template from paper and use this to cut the shelves, but check the template fits all positions first, often it won't.
Plastic shelving racks
Moulded plastic shelving units have one major advantage: great ease and speed of assembly. They are also impervious to damp, which can be a real advantage in an outbuilding.
Designs can vary, so check your unit for stability. If unstable, it will need fixing to a wall or other rigid support.
Bamboo & Willow
Shelving units are occasionally seen made from bamboo and similar materials, often with woven fibre shelves. These units are only suitable for very lightweight uses.
Breeze Blocks
Occasionally breeze blocks are stacked to make supports for wood shelves. If designed and built well this can make strong units, but without sufficient means to resist sideways forces, such units would be unsafe.
Safety
Safety problems are common with shelving units. Metal units are especially prone to this. Even assembled as per instructions, these units are often a hazard.
Bracing
Many racks are supplied without adequate bracing, and a child (or adult) crashing into one could cause it to fold over sideways, crushing anyone underneath it or caught between its shelves. Due to the lever effect the forces involed in such collapses are often sufficient to crush bones or kill. Metal shelving systems are the worst offenders in this respect.
To be safe, wooden units must be non-topplable. This is easily achieved with bracing on 3 sides or fixing to a wall. Very small amounts of joint movement are acceptable since movement does not undo the fixings.
Metal systems are different in this respect, and any joint movement at all progressively undoes the bolts, causing units to become precarious. Metal systems therefore require sufficient bracing to prevent any joint movement at all.
Heavyweight units can achieve this with bracing on 3 sides, and with shallower systems by fixing to a wall.
Lighter systems also need bracing on 3 sides, but are typically too shallow to be safe without fixing to either a wall or to other shelving units to make a larger rigid structure.
All shelving racks not fixed to a wall need bracing on 3 sides to be safe. Bracing consists of a strip of wood or metal at 30 to 60 degrees attached across each of the 3 sides. The triangle shapes thus formed give the unit rigidity in all directions of movement.
2 braces are not enough. With for example left and rear bracing, the right side can still move a little and the unit twist, and this small movement causes joints to come undone.
Small triangles of metal in corners are not effective for bracing. They help lightweight shelves resist crumpling at the corners.
Stability
Lightweight metal shelf racks are frequently unstable, and can be toppled without too much difficulty. Pulling on them soon shows if they are not stable. There are 2 problems with this, firstly the potential for serious injury if a rack falls, and secondly this occasional slight movement will gradually undo the bolts, making an unsafe shelving rack into a precarious one.
Unstable racks need attaching to something to stabilise them. This is often the wall behind them. Tall shelves not next to a wall can use a strip of wood attached at the top that runs horizontally to another shelving unit or a wall. Racks fixed remotely must be thoroughly braced to achieve a completely stiff system. Any movement in these units is unsafe.
Torque
Doing up metal unit fixing bolts with pliers does not give a safe structure. Use a socket or spanner to obtain sufficient torque.
Maintenance
Bolts loosen in metal shelving racks, even when braced and stabilised. They just loosen much more slowly, such that an all round tightening is only needed every 1-2 years. This maintenance should not be overlooked or the racks gradually become weak, unstable and unsafe.
Racks without sufficient bracing (on 3 sides) can loosen quickly. In the worst cases an unbraced rack can loosen to the point of collapse in a day or two.