Air Gap Method: measurements of airflow inside air gaps of walls

Abstract

Purpose

Water damage is a severe problem in modern construction, causing economic loss and health implications. By using the patented Air Gap Method inside building constructions, harmful water in the construction can be dried out. The method drains and ventilates air gaps inside walls and floors with an airflow driven by thermal buoyancy caused by a heating cable in vertical air gaps. This paper aims to investigate this method and measurements of airflow inside air gaps of walls.

Design/methodology/approach

This study investigates the measured correlation between the power of the heating cable, the difference of temperature inside and outside the air gap, and the airflow. Data are collected by experimentation with a full‐scale constructed wall.

Findings

The study finds that airflow increases with raised temperature difference between the air gap and room and with raised power of the heating cable. The measured airflow reaches values up to 140 m³/metre wall and day for one cable. A small increase in temperature, between 0.2 and 0.3 ^oC inside the vertical air gap results in an air flow of approximately 60 m³/metre wall and day. The air change rate per hour for the air inside the wall construction varies between 15 times for a 6 W/m cable and 37 times for a 16 W/m cable.

Practical implications

The method provides the means to build houses in a more robust way, minimising the negative effects of water damage. This investigation provides an understanding of how temperature and ventilation are related in this method of construction.

Originality/value

The issue of ventilated construction is rarely investigated in scientific research.

Citation

af Klintberg, T. and Björk, F. (2008), "Air Gap Method: measurements of airflow inside air gaps of walls", Structural Survey, Vol. 26 No. 4, pp. 343-363. https://doi.org/10.1108/02630800810906584