According to the Ordinance on Hazardous Substances, companies in which safety risks may arise from hazardous explosive mixtures must prepare explosion protection documents. Almost every electroplating plant is affected by this legal obligation.
Of course, the aim in this case is to guarantee the safety and health of employees and to protect the environment from damage. The explosion protection document is a risk assessment that is carried out and documented either by the employer or a competent person appointed by the employer. This is the intention of § 5 Para. 2 of the Occupational Health and Safety Act (ArbSchG).
Laws define terms
The Hazardous Substances Ordinance (GefStoffV) also provides for an explosion protection document. However, it makes sense to first check whether this is necessary at all. It is therefore practical to first determine whether substances, mixtures and products can form explosive mixtures due to their properties and the way in which they are created, present or used in the workplace. This requirement applies under atmospheric conditions, between a temperature of minus 20 °C and plus 60 °C, an air pressure of between 0.8 bar and 1.1 bar and an oxygen content in the air of around 21 %.
This risk analysis must be carried out regardless of the number of employees, and for the first time before the planned activities begin. If it is determined that employees or third parties are at risk from the formation or occurrence of hazardous explosive mixtures, an explosion protection document must be drawn up.
But what is an explosive mixture anyway? The definition is provided by Section 2 (10) of the Hazardous Substances Ordinance. The paragraph states: "An explosive mixture is a mixture of flammable gases, vapors, mists or dispersed dusts and air or another oxidizing agent that reacts in a self-propagating flame propagation after an ignition source becomes effective, generally causing a sudden increase in temperature and pressure." Paragraph 12 of the same section of the Hazardous Substances Ordinance adds: "A hazardous explosive mixture is an explosive mixture that occurs in such quantities that special protective measures are required to maintain the health and safety of employees or other persons."
Functioning, well-functioning exhaust air systems ensure explosion safety (Photo: Alexandr Ivasenko /StockAdobe.com)There is no binding form defined by law for the explosion protection document. However, a structure has emerged that was laid down in the former Ex Directive BGR 104, which is now DGUV Rule 113-001:
1. indication of the company/part of the company/work area
2. the names of the persons responsible for the company/part of the company/work area, date of creation and annexes
3. a brief description of the structural and geographical conditions (e.g. site plan, building plan, layout plan, building or system ventilation)
4. a description of the plant/process/activity
5. the substances used or produced with the safety-related parameters for assessing the explosion hazard (note: under non-atmospheric conditions, the parameters may deviate and may have to be redetermined!) as well as the quantities used and the processing state of the substances
- Flammable liquids and gases e.g:
- Flash point of flammable liquids
- Lower and upper explosion limit
- Density ratio to air
- Ignition temperature (temperature class)
- Explosion group
- Oxygen limit concentration
- Vapor pressure of flammable liquids
- Combustible dusts e.g:
- Particle size distribution (median value)
- Lower explosion limit
- Minimum ignition energy
- Maximum explosion pressure
- KSt value
- Minimum ignition temperature of a dust cloud
- Minimum ignition temperature of a dust layer (at 5 mm dust layer - glow temperature)
- Oxygen limit concentration
6. assessment of the hazard
- Can explosive mixtures occur in the area of the system to be assessed or inside equipment?
- Are the expected quantities of explosive mixtures hazardous due to the local and operational conditions?
7. explosion protection measures and concept
- Measures that prevent or limit the formation of hazardous explosive mixtures (avoidance of explosive mixtures in accordance with TRGS 722) and zoning (definition of areas within which the occurrence of hazardous explosive atmospheres cannot be safely ruled out)
- Measures to prevent the ignition of hazardous explosive mixtures (TRGS 723)
- Design measures that limit the effects of an explosion to a harmless level (TRGS 724)
- Organizational measures (e.g. instruction, work approval, coordination, tests, inspection rounds, cleaning, etc. - these only as a supplement to the technical measures)
Appendices or attachments are often attached to the explosion protection document, but these are stored separately from the actual document, for example on a computer or on an external storage medium. In such a case, a reference to the actual location of these attachments is sufficient.
Specialist knowledge of the person responsible
The law also stipulates that a risk assessment in the form of an explosion protection document may only be carried out by a competent person. In addition, the relevant legal basis states that operators or contractors who do not have this knowledge or who do not feel confident in preparing the document must seek expert advice. In practice, this means that the owner of an electroplating company, for example, must obtain the services of an external expert or provide himself or an employee with the appropriate skills through suitable training measures.
The risk assessment regarding explosion protection and therefore also the explosion protection document must be reviewed regularly. However, there is no legal definition of what "regularly" means. One thing is certain: if production processes, substances or systems and system components change frequently, an annual review of the circumstances is recommended, or a biennial review in the case of infrequent changes. This must be documented in writing, stating the date.
An update is always required if
- changes to the working conditions, including changes to work equipment, the system or the substances used or produced are relevant to safety
- changes to an installation or workplace in a potentially explosive atmosphere have an impact on the explosion protection concept
- new information is available, in particular findings from accidents, or
- the examination of the suitability and function of the protective measures has shown that the specified protective measures are not effective or not sufficient.
According to DGUV Information 213-106, the company management must assess whether and to what extent explosion protection plays a role in the aforementioned cases, if necessary with the assistance of an expert.
Conclusion:
An explosion protection concept could emerge from an explosion protection document. This should document how the company or its management intends to prevent explosions and thus their effects, and what measures and precautions have been taken. One example of this would be to divide affected areas into so-called "explosion zones".
Legal basis
The paragraphs from the laws to which the text or passages in the main essay refer are listed here. The basic principles are therefore not exhaustively listed, which would go beyond the scope of this info box.
Occupational Health and Safety Act
§ 5
(I) The employer shall determine which occupational health and safety measures are necessary by assessing the risks to employees associated with their work.
...
(III) A hazard may arise in particular from
- the design and equipment of the workplace and the workplace
- physical, chemical and biological effects
- the design, selection and use of work equipment, in particular working materials, machinery, equipment and installations and the handling thereof
- the design of work and production processes, work sequences and working hours and their interaction
- inadequate qualification and instruction of employees
- mental stress at work.
Hazardous Substances Ordinance
§ 2
(I) Hazardous substances within the meaning of this Ordinance are
- hazardous substances and mixtures according to § 3
- substances, mixtures and articles which are explosive
- substances, mixtures and articles from which substances according to number 1 or number 2 are produced or released during manufacture or use
- substances and mixtures which do not meet the criteria in numbers 1 to 3, but which may endanger the health and safety of employees due to their physico-chemical, chemical or toxic properties and the way in which they are present or used in the workplace
- all substances to which an occupational exposure limit value has been assigned.
...
(X) An explosive mixture is a mixture of flammable gases, vapors, mists or airborne dusts and air or another oxidizing agent which, when ignited by a source of ignition, reacts in a self-propagating flame propagation, generally causing a sudden rise in temperature and pressure.
...
(XVI) A person is deemed to be competent if he has the necessary specialist knowledge to carry out a task specified in this Ordinance. The requirements for specialist knowledge depend on the respective type of task. The requirements include appropriate professional training, professional experience or recent professional activity as well as participation in specific further training measures.
...
(XVII) Anyone who has extended their existing specialist knowledge by attending an officially recognized specialist training course is deemed to be competent. Depending on the field of activity, it may also be necessary to complete the course with a successful examination in order to acquire the expertise. Furthermore, anyone who has a qualification recognized as equivalent by the competent authority or specified as equivalent in this Ordinance is also deemed to be competent.
§ 6
(I) As part of a risk assessment as part of the assessment of working conditions in accordance with § 5 of the Occupational Health and Safety Act, the employer must determine whether the employees carry out activities involving hazardous substances or whether hazardous substances may be produced or released during activities. If this is the case, the employer must assess all resulting risks to the health and safety of employees from the following points of view
- the hazardous properties of the substances or mixtures, including their physico-chemical effects
- information provided by the supplier on health and safety, in particular in the safety data sheet
- the type and extent of exposure, taking into account all routes of exposure; the results of the measurements and investigations in accordance with Section 7 (8) must be taken into account here
- Possibilities of substitution
- Working conditions and procedures, including work equipment and the quantity of hazardous substances
- Occupational exposure limit values and biological limit values
- Effectiveness of the protective measures taken or to be taken
- findings from occupational medical check-ups in accordance with the Ordinance on Occupational Health Care.
...
(XI) The risk assessment may only be carried out by competent persons. If the employer does not have the relevant knowledge himself, he must seek expert advice. In particular, the occupational safety specialist and the company doctor can be experts.
