What shall one pay attention to while choosing a pallet racking system
While organizing storage facilities at the enterprise a wide range of decisions is to be taken by the logistic department, one of them being a choice of the right racking system. As the purchase of storage equipment is a long term investment, the specialists shall consider seriously the possible supplier.
Usually considered are such factors as price and payment conditions, equipment quality, maintenance (incl. on site surveillance check and quick replacement of damaged parts), rendering of additional services (measurement of the warehouse, layout modeling, consulting and on site installation assembly), after-delivery of components in the future, etc. The best price / quality value is a criterion for choosing the best supplier of storage equipment.
IMVO introduces a comprehensive study that professionally estimates a long-term investment object - storage equipment - and further successful use of it.
Nowadays, the production of racking systems is rapidly growing all over the world, especially in Asian countries. Most manufacturers claim their products to meet the latest requirements of the Directives FEM & EN, and that their production is certified according to ISO 9001. However, very often the product is sold in the market at low price. At the same time customers get assured through advertisements that the product they consume is of high quality and meets all safety requirements. The truth is, most of these pallet racking systems are only copies of well-known manufacturers’ designs, or are of local production and made without any special calculations and tests.
Why Directives FEM & EN are so important?
Constantly rising cost of land causes high storage of goods to become a common practice In the modern market, with height of stored palletized goods to be over 10 m, or even 14 m in case of very narrow aisle storage operations.
Some consumers may notice absence of any visible beam deflection under high loads, but do not pay adequate attention to the designed strength and allowable load on the racking section, which can bear up to 7-8 levels of storage.
This error can cost the manufacturer a lot. If storage systems do not meet all safety requirements, the employees are at risk every day. On the other hand there is a significant risk of damage to the goods as a result of deformation and breakdown of low-quality storage equipment.
Therefore, IMVO considers it necessary to comply with the legal European Directives.
EN 15635: Steel static storage systems – Application and maintenance of storage equipment.
EN 15620: Steel static storage systems – Adjustable pallet racking – Tolerances, deformations and clearances
EN 15629: Steel static storage systems – Specification of storage equipment
EN 15512: Steel static storage systems – Adjustable Pallet racking systems – Principles for structural design
What shall one pay attention to while choosing a pallet racking system?
Usually the customer is provided with the following information:
Cost of individual elements of racking.
Warehouse capacity – number of pallet places.
Maximum beam deflection.
All manufacturers of racking systems state the permissible load on a racking section to be XXXX kg, permissible load on a pair of beams to be XXXX kg.
However, sometimes this information is not sufficient for taking an optimal decision.
When choosing a supplier the following shall be taken into account:
- History of the supplier, references to the related materials (certificates), availability of recommendations
- Availability of production facilities and possibilities for testing
- Confirmation documents about the conducted tests
- Quality of material (steel grade) used in the production process
- Yield strength (depending on the grade of steel) - defined as YS
- Tensile strength (depending on the grade of steel)
- Deflection of the beam central point
- Strength safety factor
- Type of beam-to-upright engagement
- Corrosion protection of racking and its elements
- The number of sections and levels of storage
- Load tables of frame sections and beams
- Availability and description of installed racking protection devices
- Availability of bracing, beams of portal linkage for installation of single racks, presence of earthquake resistant bracing.
Why is it preferable to work with a Ukrainian manufacturer?
On request IMVO can provide its customers with a list of metal suppliers (Ukrainian enterprises), copies of certificates for materials, references from major consumers and list of racking testing.
Many companies claim their product to meet the standards, though they have never carried out any tests. Any testing should be accompanied by a set of detailed pictures of various tests and reports based on the results of tests. If the product has been tested, the reports and photographs should be available.
IMVO regularly conducts product testing, documentary proof of this can be provided to the customer upon request. Quality of IMVO products is confirmed by certificates UkrSEPRO. All production processes at the enterprise meet ISO 9001:2008.
While operating the storage equipment there may be a need for replacement or after-delivery of individual elements for routine repair or extension of storage space for goods. The following questions come up:
Will a small Asian supplier be active in the market in 3 years?
What will be the cost of after-delivery of several components for such products?
What is the delivery time?
We, as a company that has been producing racking for many years, can guarantee our customers an uninterrupted and short-time delivery of racking elements for further warehouse extension or routine repair. Having got its own research and development department our company is capable of developing and implementing innovative solutions that are utmost adapted to the requirements of any customer.
Let us on consider the technical parameters of products.
One of the most important characteristics of storage equipment, which unfortunately is not always taken into account, is steel grade, which is used for manufacturing individual elements.
At present widely available steel grades are S235JR or St3ps, they can be ordered in rolls of standard width. However, racking frames require a material with better physical properties than the one used for manufacturing beams.
In some countries, steel with high physical properties is not available; it shall be ordered in limited quantities long time in advance (f. e., steel with yield strength 350-420 MPa shall be ordered several months in advance with a minimum quantity of 70 -140 tons).
This causes some manufacturers to use steel with lower yield and tensile strength. On request of the customer, they provide samples of racking elements that may have a bigger thickness than the elements of well-known manufacturers. There may be a mistaken belief that these elements have high strength. Unfortunately, often this is done to compensate for the fact that lower quality steel was used. Most Asian manufacturers use mild steel Q185 (analogues to St0 and St1).
When choosing a product we recommend to make sure that the mechanical properties of the structure correspond to the planned equipment load, and request from the manufacturer a certificate confirming the mechanical properties stated earlier.
Depending on the behavior of the racking element after removing the load, defined are the following deformations:
- elastic (or reversible) if an element after eliminating affects that caused deformation fully recovers its original shape and size (due to the accumulated potential energy);
- residual (or irreversible), if an element after removal of applied forces or other affects does not recover its original shape. Residual deformation is in turn divided into plastic deformation caused by increased tension and creeping deformation that occurs under load in course of time.
- Yield strength is usually measured in N/mm2 or MPa.
- Together with the steel grade also yield strength is to be indicated.
Tensile strength is a property of the material needed for determining the residual deformation of the material for bearing elements of the structure.
Together with the steel grade also tensile strength is to be indicated.
Beam mid-point deflection
The maximum mid-point deflection of a beam according to EN or FEM10.02.02 shall not exceed 1/200 of the beam length. This means that the allowed deflection from the horizontal position under load is 2700/200 = 13.5 mm, after removing the load the beam returns to its original position. So, when the beam is loaded you will see a small "bend".
Make sure beam deflection does not exceed 1/200; if the deflection is bigger then the bearing capacity of beams does not meet requirements of EN and values stated by the manufacturer.
Safety factor is used for safety at the facility, and is 1.4 according to EN, i. e. 40% in the calculations of absolutely ultimate state, and 1.0 in the calculation of the operational ultimate state. Request from your suppliers a confirmation that the product has really been tested.
Absence of testing indicates that the product is intended only for the Asian market, not European. Offering cheap products under the brand name of an European manufacturer points to the fact that the product was made in Asia for the Asian market, and it can not be exported to Europe.
Why it is important to have a high safety factor?
Analyze the processes that take place daily in your warehouse: handling equipment weighing up to 4000 kg moving with a load at a speed of 10 km / h, aisles between rows being 3-4 m, loads up to 1000 kg lifted to a height of 10 m.
Type of beam-to-upright connection is one of the most important factors affecting the calculation of allowable loads.
Frontal wedge or slot connection
Slot connections due to big clearances do not allow storage at height over 5-6 m.
Anticorrosive protection of racking and its elements
Most Asian manufacturers use lead paint or powder to give the product a glossy finish. It is unacceptable for warehouses, where food, beverages and pharmaceuticals are stored. Any scratch during operation may cause penetration of small particles of lead on pallets or on the surface of the products below.
Make sure that the supplier does not use lead in powder coating.
Dimensions of sections and levels of storage
Ask the supplier about all the possible size of upright frames and beams to evaluate the different possibilities of loading. Even the type of fixation to the floor is important because it can significantly add to the total overall length of the system.
All sizes of racking system shall be stated in the technical specification and summarized in tables; that will make possible a comparison between different suppliers.
For example, if the height of the beam profile at one supplier is 125 mm at loads of 3.0 tons per a pair of beams, and another supplier offers a 140 mm high beam profile for achieving the same level of load, ask yourself, why should it be so. Most likely steel of lower grade was used in the production.
Compare the allowable load on the upright frame sections relative to position of the first pair of beam above the ground. Height of the first beam level is crucial in terms of the correct choice of permissible loads on the racking frame. You can view load charts for different heights of first level storage.
If load charts are not available request them from the manufacturer.
Tables with beam and frame bearing load
The important point is how manufacturers presents load charts. Tables should be the result of detailed testing. Calculations of allowable loads of the second critical state are rather complicated procedures that require special computer aided programming.
We hope that this research will be useful for you, and will guide you on ordering a pallet racking. Do not sacrifice a guarantee of safety at your facility, tempted by low cost of the equipment.
Take your time to study the detailed technical data and do not limit yourself just to price while comparing commercial offers from different manufacturers.
Request from your supplier a confirmation of conformity of racking and individual elements to the stated technical data. Absence of such documents points to the fact that the equipment does not meet the stated parameters.
Regular research and product testing to ensure quality production are crucial to guarantee safe operation of equipment.
In conclusion, let us note that many companies can show you the certificate ISO 9001. However, this does not mean that their product is safe; conformity to ISO procedures and processes of production has nothing to do with the safe operation of the racking. In other words, you will get what you have paid for.
Head of IMVO Racking Systems Research and Development Dept.
Natalyuk I. M.