Inspections of electrical equipment in areas with a risk of explosion (type B premises)

What areas with a risk of explosion (type B) are and who they concern

Electrical equipment intended for use in an atmosphere with a risk of explosion of gases, vapours or dusts is designated electrical equipment of class I, that is, the class with the highest level of risk (Section 4(1)(b) of Government Decree No. 190/2022 Coll., Section 3(2) of Act No. 250/2021 Coll.). A lightning protection system that protects such equipment also belongs to class I (Section 4(1)(e)). Company authorisations and inspection technicians' certificates for this equipment carry the distinguishing mark “equipment in areas with a risk of explosion” – type B (Annexes 3 and 5 of Government Decree No. 190/2022 Coll.). This is where the common term “type B premises” comes from.

In terms of external influences, this is influence BE3 – risk of explosion, that is, the production or storage of explosive substances, including the presence of explosive dust. Standard ČSN 33 2000-5-51 ed. 3 (tables ZA.1 and ZA.1N) distinguishes explosions of combustible dusts (BE3N1), combustible gases and vapours (BE3N2) and explosives (BE3N3). Fire risk (BE2) is a different influence with different requirements.

Beware of one exception: equipment with a current or voltage that would not otherwise pose an increased level of hazard is not designated equipment. However, this does not apply to equipment intended for use in an atmosphere with a risk of explosion of gases, vapours or dusts (Section 3(2)(e) of Government Decree No. 190/2022 Coll.). Below are the types of operations where such areas often occur. Whether they exist at your site is determined by the documentation (see the next section).

• Petrol and LPG filling stations, dispensing points and loading and unloading areas
• Paint shops, paint mixing rooms, powder coating shops and operations using solvents
• Stores of flammable liquids and gases
• Gas plants and biogas stations, wastewater treatment plants with areas where gas can accumulate
• Dusty operations: mills, silos, woodworking with sawdust extraction, feed mills
• Chemical and pharmaceutical plants, battery rooms where traction batteries are charged
• Municipalities and towns: wastewater treatment plants, gas boiler rooms and regulating stations with designated zones, technical services

Do these rules apply to you? The documentation decides, not guesswork

Whether a plant contains an area with a risk of explosion and how far it extends is determined in advance – in the protocol on determining external influences and in the classification of hazardous areas (zones). The inspection technician uses them to check that the equipment on site matches the designated areas. During the examination under Annex 1 part A (f) of Government Decree No. 190/2022 Coll., the technician also verifies that the classification and marking of areas in terms of external influences are justified.

If the protocol is missing or out of date (the technology, stored substances or ventilation have changed), that is the first thing to resolve. We offer the protocol on determining external influences as a separate service – see the page “Protocol of external influences (PUVV)”.

What we inspect

An inspection does not replace the explosion protection document or the risk assessment. The employer provides both under Government Decree No. 406/2004 Coll., on more detailed requirements for ensuring safety and health protection at work in an atmosphere with a risk of explosion. The inspection verifies that the electrical equipment is safe and corresponds to what these documents specify.

• Electrical installations in areas with a risk of explosion and their connected parts: switchboards, wiring, cable entries, luminaires, sockets, controls
• Electrical equipment of technologies: pump motors, fans and extraction, heating, measurement and control in explosion-proof design
• Equipotential bonding and earthing
• Safety functions: emergency stop, interlocking, monitors, signalling, surge protection (Annex 1 part B point II of Government Decree No. 190/2022 Coll.)
• Lightning protection of buildings that contain areas with a risk of explosion
• Operating documentation: whether it is complete and matches the actual state

Initial, periodic and extraordinary inspections

An inspection is also required after a change in overload and short-circuit protection, protection against electric shock, or the properties of lightning protection (Section 6(4) of Government Decree No. 190/2022 Coll.).

What is often forgotten: class I designated electrical equipment can be put into operation only on the basis of a certificate from an authorised organisation (Section 6(6) of Government Decree No. 190/2022 Coll., Section 6(1)(b) of Act No. 250/2021 Coll.). The operator keeps the certificate for the whole time the equipment is in operation; it also serves as a basis for periodic inspections (Annex 2 part A point II (f)).

• Initial inspection – in every case after installation is completed, and after repair or relocation as needed, so that safety is always verified (Section 6(2)(c) and (d) of Government Decree No. 190/2022 Coll.); after reconstruction it is required by Section 20(6) of Act No. 250/2021 Coll.
• Periodic inspection – repeated at intervals under Annex 4 of Government Decree No. 190/2022 Coll. and the inspection, maintenance and revision rules (Section 7(1) and (5))
• Extraordinary inspection – when there is a reason for it, e.g. after an accident, fire, leakage of a flammable substance, flooding, a lightning strike, or when previous inspection reports are missing; the reason is stated in the inspection report (Section 10(1)(e) of Government Decree No. 190/2022 Coll.)

How often: a 1-year interval under Annex 4 of Government Decree No. 190/2022 Coll.

On the internet you will find intervals of 1, 2 and 3 years. The government decree decides: Annex 4 of Government Decree No. 190/2022 Coll. sets a basic maximum interval of 1 year for periodic inspection of “areas with a risk of fire and explosion”.

Where the other numbers come from: ČSN 33 1500, as amended by Z3, gives 2 years for environments with a risk of fire or explosion (BE2, BE3) and, in a note on the risk of explosion of gases and vapours, refers to an interval of at most 3 years under ČSN EN 60079-17. Where several intervals apply, the shortest is used, so 1 year applies.

• If several intervals apply to the equipment, the shortest one is used (Annex 4, additional information (a))
• The rule “it is enough to do it by the end of the year in which the interval ends” does not apply to intervals of up to one year (additional information (b)). An annual inspection must therefore be done within 12 months of the previous one
• An operator with a preventive maintenance plan, in which regular checks and maintenance minimise the risks, may set intervals of up to double in it (additional information (c)). Without such a plan and records of checks, the interval stays at 1 year
• If the manufacturer states a shorter interval in the accompanying documentation, the manufacturer's interval applies (Section 7(2) of Government Decree No. 190/2022 Coll.)
• Lightning protection of buildings with a risk caused by explosive materials: a visual check at least every 6 months and a full inspection once a year (Annex 4, additional information on LPS intervals (b)); critical systems also include class I designated electrical equipment (c)

What to prepare before the inspection

Equipment for explosive atmospheres is placed on the market under Government Decree No. 116/2016 Coll., on conformity assessment of equipment and protective systems intended for use in an atmosphere with a risk of explosion. The certificates and the markings on rating plates come from the conformity assessment, and during the inspection we compare them with the designated area. If any document is missing, we state in the inspection report what needs to be added. Without the determination of external influences and zones, however, it is impossible to verify that the equipment matches the area. Moreover, missing accompanying or operating documentation, where it was issued, is a condition endangering operational safety under Section 20(3)(c) of Act No. 250/2021 Coll.

• The protocol on determining external influences, if it is not part of the documentation (Annex 2 part A of Government Decree No. 190/2022 Coll.)
• The classification of hazardous areas (zones) with a drawing of their extent
• The explosion protection document under Government Decree No. 406/2004 Coll., if one has been drawn up
• Project or as-built drawings and diagrams of the switchboards
• Accompanying documentation of equipment for explosive atmospheres: type of protection marking, temperature class, certificates and manufacturer's instructions
• The certificate of an authorised organisation for class I equipment, if one was issued
• Previous inspection reports, records of examinations, maintenance, repairs and rectified defects
• The inspection, maintenance and revision rules, or the preventive maintenance plan
• A contact for the person responsible for the electrical equipment and for running the technology

How the inspection works

1. Documents – we go through the protocol on external influences, the zone classification, previous reports and the equipment documentation; based on them we propose the scope and prepare a non-binding quotation
2. Safe conditions – with the person responsible for operations we agree when and how measurements can be taken. Tests in a potentially explosive atmosphere require suitable safety measures (ČSN 33 2000-6 ed. 2, clause 6.4.3.1), so we plan measurements for a shutdown or after ventilation, for example
3. Documentation check – whether it matches the actual installation and is complete (Annex 2 part B of Government Decree No. 190/2022 Coll.)
4. Examination – we verify that the design of the equipment matches the external influences and that the classification of areas is justified; we check marking, diagrams, warning signs and accessibility (Annex 1 part A), and for equipment in explosive atmospheres also the condition of enclosures and cable entries
5. Measurements and tests – continuity of protective conductors and bonding, insulation condition, automatic disconnection of supply, functional tests and safety devices (Annex 1 part B)
6. Evaluation – we compare the results with the documentation and regulations and evaluate the documents in their mutual context
7. Inspection report – a conclusion on whether the equipment is safe to operate, defects with a reference to the provision breached, and the recommended interval to the next inspection (Section 10 of Government Decree No. 190/2022 Coll.)

What we follow

Older equipment is assessed under the regulations in force when it was put into operation, until its reconstruction (Section 3(5) of Act No. 250/2021 Coll.).

• Act No. 250/2021 Coll. and Government Decree No. 190/2022 Coll. – operator's obligations, scope of inspection, intervals and content of the inspection report
• ČSN 33 1500 and ČSN 33 2000-6 ed. 2 – inspection of electrical equipment and low voltage installations
• ČSN 33 2000-5-51 ed. 3 – determination of external influences including BE3
• ČSN EN 60079-10-1 – classification of hazardous areas with explosive gas atmospheres
• ČSN EN 60079-14 – design, selection and erection of electrical installations in explosive atmospheres
• ČSN EN 60079-17 – inspection and preventive maintenance of electrical installations in explosive atmospheres
• ČSN EN 60079-19 – repair, overhaul and reclamation of equipment for explosive atmospheres

Who may carry out the inspection and what you receive

An inspection may be carried out only by a company with an authorisation and an inspection technician with a certificate of professional competence (Section 20(2)(c) and (d) of Act No. 250/2021 Coll.). The certificate must cover equipment in areas with a risk of explosion (type B under Annex 5 of Government Decree No. 190/2022 Coll.) – a technician whose certificate covers only areas without a risk of explosion may not carry out such an inspection. With us, the inspection is carried out by an inspection technician with a TIČR certificate.

• An inspection report in electronic form signed with a recognised electronic signature (Section 10(1)(d) of Government Decree No. 190/2022 Coll.)
• A list of documents and their evaluation, measured values and a list of measuring instruments
• An overview of defects with a reference to the provision breached and a clear description of what to repair
• The recommended interval to the next inspection and, on request, deadline monitoring

When the inspection fails

The operator must remove defects endangering safe and reliable operation without undue delay after the inspection report is issued. Other defects are removed according to their severity within the deadlines imposed by the labour inspectorate and, if no inspectorate check has taken place, within deadlines the operator sets itself (Section 20(5) of Act No. 250/2021 Coll.). Equipment whose condition immediately endangers safety must be disconnected without delay and secured against reconnection and, where that is not possible, repaired without undue delay (Section 7(8) of Government Decree No. 190/2022 Coll.). After the repair we verify that the defects have been removed and issue a new inspection report.

Operation without an inspection carried out within the set interval and scope is a condition endangering the safety of work and operation (Section 20(3)(a) of Act No. 250/2021 Coll.). In an explosive atmosphere the risk is even higher – a spark or hot surface of unsuitable equipment can cause an explosion.

Free inspection deadline monitoring

An annual interval passes quickly, and the shift to the end of the calendar year does not apply to it. We record the date of your next inspection in our register and contact you in advance, so there is time to plan the shutdown. Just register on the “Free inspection reminders” page – free and without obligation. We set the price of the inspection individually according to scope, and the quotation is non-binding.

We are based in Pardubice. We also carry out inspections in explosive atmospheres in Prague, Hradec Králové, Náchod, Rychnov nad Kněžnou and their surroundings.