Many differences exist between countries in the requirements and regulations for ventilation of dwellings, offices, classrooms and other spaces. Sometimes the variation of the ventilation requirements for the same building type between countries is more than a factor of five. There are strong drivers, e.g., climate change, to reduce energy consumption for HVAC and therefore these variations are worth examining. Before reducing ventilation rates, it is critical to understand the reasons behind them. Demand control to adjust the ventilation flows is becoming more common in many countries, but the control approaches are quite different, for instance humidity versus CO2 control. This document provides insight into the reasons for ventilation requirements across different countries to provide policy makers and standardization committees information for the discussions about ventilation. Although this document doesn’t discuss the relation between pandemic management and required ventilation levels, it can help the discussion to know which drivers are behind current regulation.
An overview of results of this survey from 29 countries show large differences in ventilation requirements for dwellings, as well for living rooms and so-called “wet rooms” (kitchen, toilet, and bathroom) In this report we have defined a methodology to compare the requirements from country to country, which are expressed in different ways. The requirements can depend on dimensions of rooms, number of persons per room, number of rooms, and ventilation system type. For example, sometimes the requirements are expressed per person, sometimes per m2 floor area, mostly in volumetric flow rates but also in air change rates. In this study, assumptions were made for room size and occupancy to compare the ventilation rates. The data gathered for AIVC countries are based on an input from individuals; the data for non AIVC countries are taken from literature. Not all country information came from experts in the ventilation field. To understand ventilation requirements in most cases also requires knowledge of the building regulations and laws.
The rationale behind the ventilation requirements includes the following elements:
- Human odour: Human bioeffluents, often with CO2 as marker criteria
- Moisture: Human activities (e.g., washing, showering, washing dishes, cooking)
- Health impact
- Dilution of other internally generated pollutants
- Formaldehyde emissions
- Cooking fumes and combustion products
- Bacteria, viruses
- Sick building syndrome symptoms
For habitable rooms, apart from the so-called wet rooms, almost all countries mention CO2 as indicator for bioeffluents as a rationale. For bathrooms, human activities and moisture production are the most important drivers. For toilet rooms, rationales are related to the spreading of odour to other rooms. For kitchens, diluting products from cooking processes are, as can be expected, the most important rationale.
The ratio between the highest and the lowest value between countries in terms of ventilation is larger in dwellings (3 to 10) compared to offices and classrooms (2 to 3). An explanation for this difference might be the more consistent activity in offices and schools. Many of these ventilation regulations were written in the same period (early 1990’s) and are generally based on the same available literature.