Bs En Iec 62485-2

[Heberto Calderon]

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Many organisations have safety or business critical systems and/or equipment that require a constant supply of electrical power. Failure or fluctuations in this power supply can have significant impacts including the potential for harm to building occupiers, the loss of data and business interruption.

However, there are hazards associated with battery installations that if not managed appropriately could impact on the availability of the UPS and place occupiers at harm, particularly those who may require access to the battery installation.

A battery installation is used to store electrical energy. For UPS purposes it will be in a fixed location and be permanently connected to both the load and the power supply. In addition to a UPS function, these types of system can be used for alarm systems and emergency power supply.

The type of batteries used will either be chargeable or non-rechargeable, with the former being the most hazardous. Chargeable batteries themselves will normally be lead/acid or alkaline (eg nickel-cadmium) although it should be noted that lithium i-on batteries are beginning to be utilised. In a UPS scenario, lead/acid are the most common type still being used.

Explosion and fire hazards can be created through the venting of hydrogen at an appropriate concentration and temperature that, if exposed to an ignition source particularly in a confined space can result in a violent explosion.

Electrical hazards exist through the stored energy found in batteries, which can be released quickly through both direct and indirect contact with the battery causing electric shock and potential fire hazards due to short circuits.

Clearly a suitable and sufficient risk assessment will need to be completed in relation to the battery installation, taking account of various legislative requirements such as those contained in the Control of Substances Hazardous to Health Regulations (for chemical exposure) and the Dangerous Substances and Explosive Atmospheres Regulations (in relation to the release of hydrogen).

One of the key design requirements relates to ventilation. Hydrogen and oxygen, when vented (either from venting batteries or due to a release valve) into the surrounding atmosphere can create an explosive mixture when the concentration of hydrogen exceeds the lower explosive limit (LEL) of 4% and up to the upper explosive limit (UEL) of 75%.

There are many factors that will impact on dilution including rate of hydrogen production, location of batteries in an area, size of the area where batteries are located and factors that could impede natural ventilation.

Both the HSE guidance and BS EN IEC 62485-2 provide the necessary formula that can be used to calculate the necessary flow-rates. In summary, because hydrogen is buoyant air inlets should be located at low level and outlets at high level. Clearly location of any battery room/enclosure will determine the need for suitable air ducting to remove gases to atmosphere.

Protection from indirect contact can be achieved through various means such as the use of automatic disconnection of supply, non-conducting locations, insulation and electrical separation. It should also be noted that any stands or cabinets made from metal must also be insulated or connected to the protective conductor.

Access to the location of the batteries should also be controlled with access limited to those with the necessary authority to undertake tasks such as charging, inspection, and maintenance. Competency is another key risk control element and whether personnel are in-house or third-party contractors, competency checks should be undertaken.

It is also essential that any instructions for use, installation and maintenance provided by the battery supplier are displayed within the vicinity of the battery so that they may be followed during maintenance cycles.

As mentioned above, electrolytes can be corrosive and/or poisonous and as such the main measures to protect persons involved in activities such as maintenance will involve the use of personal protective equipment (eg gloves and goggles) and readily available first-aid facilities in the event of any incident occurring.

Inspection and maintenance regimes should not only include the condition of the batteries and associated terminals and connections but also any safety systems such as ventilation systems and the condition of any stands, cabinets and flooring within the location where UPS batteries are located.

The battery is tested in accordance with DIN EN 50272-2 / IEC 62485-2 and the manufacturer's specifications. It serves to ensure that the battery system is handled in accordance with the standards and operated in accordance with the product. This ensures that faults are identified as quickly as possible and that appropriate actions are taken in advance to avoid faults and eliminate possible faults.

I have recently inspected a Storage / Workshop that contains marine systems and I have little experience of implementing DSEAR. Some systems are powered by Lithium batteries. I have been boning up on DSEAR requirements but can find nothing on storage of lithium batteries. I know they are a UN Hazard Class 9 so am I right in thinking they do not come under DSEAR provisions?

What about battery charging areas? They have a dedicated charging area with LEV etc but it does not appear to be classified as a DSEAR Hazard Zone by building management and there is no DSEAR RA though there is a SWOP and operational activity RA for battery recharging.

I believe they should have a DSEAR RA undertaken. My understanding is that the Building owner should do this under the arrangements in place (in terms of identifying Haz Zones / Building plans etc) but the user also has an obligation to DSEAR RA it's activities and processes (eg the Fuel Cube which is temporary and deployed). I thought I'd ask these questions on here before formally reccommending as there will likely be some push-back and I want to ensure my ducks are in line beforehand.

I intend to advise that they contact the Building owner to conduct a DSEAR RA and we conduct a DSEAR of our user storage and processes which will identify the hazardous materials and capture where our usage scenarios (such as refilling etc) may have impacts and what mitigations are in place. We may have in-house fire officer or similar who can come across to do this or bring someone in. Is there a set periodicity for DSEAR RAs?

Regarding Risk Assessment frequency. Every 3 years maximum unless there is a change to how the process is conducted, substance being used, quantities being used, room/plant layout affecting ventilation or other changes which might cause concern and warrant an update of the risk assessment.

Carefully vet your proposed DSEAR Assessors (And this is difficult) as 95% of those advertising and conducting these works should be considered as DSEAR Dabblers as opposed to competent DSEAR Assessors. This leads to over or under classification and expensive ATEX works being recommended which otherwise would not have been required.

Unfortunately the websites and lists off services offered is no firm guide as to the competence of the assessors behind the website, and with no governance within the field you are in the lap of the gods as to whom you choose and what you end up with.

From the DSEAR point of view batteries are of interest because they release hydrogen as part of the re-charge cycle - as a result of the electrolysis of the electroylyte. The rate of hydrogen release is given by Faradays Law. The standard mentioned BSEN 62485-2 Safety requirements for secondary batteries and battery installations does not consider lithium batteries because they don't release any gases under normal operation - only under thermal runaway - which is an electrical fault rather an expected normal gas release - so not a DSEAR issue. Hazarous area classification doens't consider gross failure of a system.

The HSE guidance for battery charging gives a 1m hazardous area Zone 1, which is extremely conservative - but an easy distance to remember. If you calculate the hazardous area following the standard, the hazardous area will be much less.

Diesel - John is correct about EI15. This standard also says, that provided there is no mechanism for a pressure/spray release, where a material has a flash point at least 5*C more than ambient temperature then no hazardous area classification is required, as no vapour is released. The typical flash point given for diesel is a minimum of 55*C. The typical maximum ambient temperature in the UK is circa 35-36*C (yes I know 2022 saw 40*C in the UK)

Even though not flamamble, as John says, the risk with compressed air systems is the build up of water within the system (the water is a vapour in the air). If allowed to accumulate in an air receiver / pressure vessel, may then lead to internal corrosion of the pressure vessel. WHich over a long period of time leads to a pressure vessel explosive failure due to corrosion weakening the pressure vessel.

The follow up post and question made by mrkjd e.g. (#3 post) asked a further question about battery charging areas which I assumed was rightly or wrongly to be different to the lithium batteries mentioned in (#1 Post).

I can only confirm a persons competence within the field of DSEAR once I have review one or two of their completed DSEAR Assessments no mater how many years experience they have in conducting such works and no matter their purported competence.

DSEAR Assessments to various levels of competence pass under my nose upon a daily basis, some completed by Senior Process Engineers, some by Health and Safety Consultants from CMOSH qualified downwards, and many other independent consultants and assessors.

When you arrange for the DSEAR Risk Assessment as the client it is up to you to set the scope of works. Most clients tie the DSEAR Assessors hands by only asking them to look at what the client thinks is a DSEAR Issue.

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