The first question we have for this month is asks how best to calculate the load capacity of a mezzanine floor. Next we consider Cantilever racking and what the degree of acceptable fall back is.

Load capacity of a mezzanine floor

Q. I have been tasked with finding out the loading capacity of an area of Mezzanine flooring which was already installed within our premises. I need to understand the loading capacity and rating for the installation in line with best practice and whether there is a different rated capacity for Mezzanine flooring (industrial).

A. When initially constructed a Mezzanine floor should have been fitted with a safe load notice advising the name and contact details of the builder, as well as the maximum uniform distributed load that the floor has been designed to take, and the maximum point load which can be imposed perhaps by a wheel from a hand truck being used to move items around or even from the footplate of a bay of shelving located on the Mezzanine.

If there isn’t a load notice on the mezzanine then it might be worthwhile asking the employees that perhaps were working in the unit at the time the mezzanine was installed or perhaps asking your neighbours if they can remember who built the mezzanine. If you can find out who built the mezzanine floor then this company should be able to sift through their archives to find the file and hence the information referred to above.

Mezzanine floors are covered by the Building Regulations so the Local Authority might have something in their files that would give you the information you need including the name of the builder. It may be necessary to pay them for the time that they spend in searching for this information however this is likely to be cheaper than the final option.

As a last resort it is possible to employ a structural engineering consultant who can measure up what you have, check it to ensure it is in good condition and then to re-design the structure from first principles. This is the most expensive option and is generally only done in any of the other options are not possible. Should you eventually go this route SEMA may be able to suggest some engineering consultants who carry out this type of work or you may have some local contacts in this field yourself.

Cantilever racking and fall back

Q. We have recently had some cantilever racking manufactured and installed and the arms have a 1 degree fall back on them. I want it to be that this is sufficient due to the fact that we are loading the racking with rolls of wrap that can weigh anything from 200kg to 400kg per roll and I wouldn’t want them to roll off injuring someone.

A. It is difficult to comment without knowing the basis of the design or what was agreed in the contract between the user and manufacturer so there is little that can be said with certainty.

However, the current SEMA code for the design of Cantilever racking states that “under full working load the arm should not deflect below the horizontal (clause 3.2.2).” Some would interpret this to mean that the tip of the arm should not deflect below the heel of the arm where it is connected to the upright. Under load however this will mean that the end of the arm will droop slightly and as you describe the matter there might be a slight tendency for goods to roll to the end of the arm. SEMA interpret this requirement to mean that no part of the arm shall be below the horizontal when measured with a small spirit level at any part of the arm while under full working load. This would take account of any upright and base deflection as well, as these also both affect the overall deflection of the arm which makes this all very complex. Some manufacturers will incline the arm upwards to overcome this effect however the amount of the pre-set that is placed in the design will depend on the flexibility of the arm.

SEMA Annual Safety Conference 2022

The 2022 SEMA Safety Conference has been scheduled for Thursday, 3 November; the venue will be the National Motorcycle Museum, Solihull.

SEMA Technical Enquiries

We hope you find the above articles, and those in previous editions, interesting. If you have a query send it to us by email to and we will do our best to have it answered.

SEMA Rack Safety Awareness and Inspection Courses

SEMA runs a one-day safety course on Rack Safety Awareness and Inspection. These courses are aimed at end users, giving an in-depth look at the need for inspections, how to conduct an assessment and what actions to take when this is completed.

SEMA Approved Rack Inspectors Qualification

This qualification is aimed at professionals who conduct rack surveys as an integral and significant part of their duties. It involves delegates in undertaking an in-depth SEMA Course, together with an examination and practical assessment. CPD will be an important part of the qualification.

SEMA Publications

SEMA has 26 publications in stock – Codes of Practice, ‘Guides’ and European documents – all of which are available from our Offices.


SEMA runs a USERS Club designed to be of benefit to purchasers and users of storage equipment. Members receive newsletters, access to specialised events and discounted rates on publications and codes of practice.




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