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Ventilation for Spas

spa ventilation

In recent years, more and more spa facilities have been built. They are enjoying increasing interest among its customers.
Such places are often designed with rooms such as: fitness, sauna, salt cave, brine, sulfur/mud pools. Due to their unusual nature and functions, these buildings are very heterogeneous and thus require a specialist approach at every stage of implementation, from design to execution. Ventilation systems are exposed to various highly toxic substances as well as chemicals.

The underestimated function of the ventilation system in such facilities as well as the selection of inappropriate ventilation ductwork may cause problems. Ventilation systems need to be renovated or retrofitted after a short period of use.

The quality of the ventilation system

Substances to which ventilation ducts are exposed in places with high humidity are:

  • mineral water,
  • chloride ions,
  • sodium/calcium ions,
  • compounds of sulfur, potassium, magnesium, iodine, bromine.

The requirements for the ventilation system are specified in PN-83/B-03430/Az3 Standard. This document constitutes the basis for the preparation of the technical specification for execution and acceptance of works. The technical conditions of completion and acceptance specify the rules for products used in ventilation systems, the method of their development and the scope of acceptance activities.

Despite this, in Poland separate regulations specifying the requirements for ventilation systems for spa zones in spa facilities are still absent. When designing a ventilation system, designers often rely on their own experience in this field.

Designers and contractors of this type of systems are aware of the need to use solutions that eliminate the condensation of moisture on the components of the system and the harmful effects of chemicals on the material of the ventilation ducts.

They repeatedly manage to convince investors to purchase specialized solutions, in particular, to use stainless steel resistant to air containing moisture and chlorine compounds. However, such methods, although very beneficial from the point of view of the proper functioning of the facility, the quality of the climate provided in spas and low purchase costs, often provides losses in terms of service life with the use of plastic solutions. Often the effects of such savings can be observed in many facilities that require renovation as a result of corrosion and cracks after several years of operation.

Other effects, such as high operating costs or poor quality of the climate maintained in the hall, are less severe and are usually not noticed by users who have no experience in the use of better-quality materials. In order to change this approach, apart from the price criterion on which the decision on the selection of the offer is almost fully based, it is necessary to apply the economic calculation criterion, which would include the analysis of the costs incurred for the material from which the ventilation systems are made and operating costs.

It is necessary to develop formal requirements for materials and devices used and the method of installing a ventilation system for spa facilities. The materials most often chosen in spa zones are 316 or 316L acid-resistant steels. They meet the corrosivity classes specified in PN-EN ISO 12944-2:2001 standard.

Corrosivity Classes
Examples of environments typical for temperate climates

(for information purposes only)


C1 very low
Heated buildings with a clean atmosphere,
e.g. offices, shops, schools, hotels

Not applicable.
C2 low
Unheated buildings where condensation
can occur,e.g. warehouses, sports halls.

Low polluted atmospheres; mainly rural areas.
C3 average
Production rooms with high humidity
and some air pollution,
e.g. food processing plants,
laundries, breweries, dairies.

Urban and industrial atmospheres,
medium sulfur (IV) oxide pollution,
e.g. coastal areas with low salinity
 C4  high
Chemical plants, swimming pools, ship
and boat repair yards.

Industrial areas, coastal areas
with moderate salinity.
C5-I  very high

Buildings or areas with almost
continuous condensation and high pollution.

Industrial areas with high humidity
and aggressive atmosphere.
C5-M very high

Buildings or areas with almost
continuous condensation and high pollution.

Coastal and offshore areas of high salinity.


Nevertheless, these materials – being exposed to highly concentrated chemicals found in brine waters – undergo degradation, namely corrosion. Therefore, an alternative for these materials might be plastic which is:

  • 100% leakproof,
  • chemically resistant,
  • long-lasting,
  • easy to install,
  • lightweight.

Check corrosion resistant ventilation ductwork >>>


The specificity of a health resort/spa requires better maintenance of individual air parameters than in other places. Therefore, these zones should be adapted to the prevailing climatic conditions, regardless of the type and quality of the ventilation system installed.

Due to their unusual nature and functions, these facilities are very different and require a specialized approach at every stage of implementation, from design to execution.

The installation of ventilation systems in spas and health resorts using plastic ducts and fittings is a solution that significantly extends the service life and increases the safety level of the structure.

Looking for more information about ventilation systems for industrial purposes? Read our expert articles:

  1. How-to: Welding plastic ventilation ductwork
  2. 8 Common Dust Extraction System Mistakes
  3. Ventilation systems for swimming pools
  4. Modular Dust Extraction Ducting
  5. Plastics in ventilation