Designing water tanks: materials, technologies and regulatory requirements in Bulgaria

Water is a vital resource, both for domestic use and for industry. Every site that needs reliable storage of drinking, process or firefighting water requires a properly designed and built tank. Designing water tanks is not simply a matter of choosing a shape and a volume; it involves technical calculations, selection of materials, allowance for loads, hygiene standards and national standards.

In this guide, the professionals at ERMAX BG explain how tank design is approached professionally in Bulgaria, from the choice of material and technology to compliance with regulatory requirements.

1. Types of water tanks by purpose

Before the design itself begins, it is important to specify what type of water and what application the tank will be used for. This determines the construction, the volume and the materials.

ERMAX BG designs and builds all types of water tanks, including tanks for drinking, firefighting and process water and for rainwater storage.

2. Determining the capacity and location

Design begins with an accurate calculation of the required volume. This depends on:

1. the number of users or sites to be served;
2. the average daily water consumption;
3. the reserves for emergency or firefighting needs;
4. the terrain conditions and access to a water source.

Example: For a residential building with 20 occupants and average consumption of 150 litres/day, a tank with a minimum volume of 3 m³ is required. For firefighting needs, the standard requires an additional volume of between 30 and 100 m³ depending on the type of building (in accordance with Ordinance No. Iz-1971/2009).

The location is determined in relation to:

1. the ground level (above-ground or underground placement);
2. the availability of access for servicing;
3. temperature conditions and protection against freezing;
4. safety and access for firefighting equipment.

3. Choice of material: the basis of durability

The material is a key factor for durability, safety and maintenance. In Bulgaria, the following solutions are most commonly used:

🔹 Polyethylene (HDPE, LLDPE)

1. The most popular material for domestic and industrial tanks.
2. Resistant to corrosion, chemicals and UV rays.
3. Lightweight and easy to install even in hard-to-reach places.
4. Suitable for drinking water (where a food-contact certificate is available).

🔹 Polypropylene (PP)

1. Used for tanks with a rectangular shape or specific dimensions.
2. An excellent choice for process applications where higher heat resistance is needed.

💬 The ERMAX BG team recommends choosing according to durability and the type of water, not only by price, because the right material guarantees trouble-free operation for over 30 years.

4. Manufacturing and construction technologies

Modular tanks

Made up of separate tanks that are assembled on site.

Advantages:

1. easy transport and installation;
2. potential for expansion;
3. lower maintenance costs.

Plastic (HDPE, PP) tanks

They are made by rotational moulding or extrusion, which provides a seamless construction.

Advantages:

1. complete watertightness;
2. anti-corrosion protection;
3. lightweight construction and fast installation.

ERMAX BG uses modern technologies and certified materials that meet the requirements for durability, safety and resistance under various loads.

5. Regulatory requirements in Bulgaria

The design and construction of water tanks is carried out in accordance with the regulations and standards in force, including:

1. BDS EN 12573 / EN 12285: standards for the design and testing of plastic and metal tanks;
2. Ordinance No. 4 of 2005: on the design, construction and maintenance of water supply systems;
3. Ordinance No. Iz-1971/2009: requirements for firefighting facilities;
4. Spatial Planning Act (ZUT): obligations when constructing facilities;
5. BDS ISO 9001 and ISO 14001: for quality and environmental management systems.

Important: All tanks that store drinking water must be certified for contact with drinking water and supplied with documents of origin and leak-tightness test reports.

6. Inspection, maintenance and safety

A good design provides not only for construction but also for accessible maintenance and inspection.

The following is recommended:

1. a visual inspection of the structure at least once a year;
2. checks for sediment, cracks or leaks;
3. disinfection of drinking water tanks;
4. control of the ventilation openings and safety valves.

ERMAX BG offers a full service, from design and manufacture to installation and servicing, which ensures long-term reliability of the facilities.

7. Why choose ERMAX BG as your partner

1. Over 27 years of experience in building tanks and water management systems;
2. Certified materials and modern production technologies;
3. Individual engineering solutions according to the client's needs;
4. Projects that comply with all Bulgarian and European standards;
5. Professional installation, servicing and technical support.

Conclusion

Designing water tanks is an engineering process that requires an expert approach, accurate calculations and compliance with regulatory requirements. The safety, efficiency and long life of the system depend on the right choice of material and technology.

Trust ERMAX BG, specialists in the design and construction of tanks for drinking, process and firefighting water that meet all Bulgarian and European standards. Contact us for professional consultation and an individual quotation.