Applied Building Physics

Ambient Conditions, Building Performance and Material Properties

Hugo S. L. Hens

• Publisher: Ernst & Sohn
• Year: 2016
• ISBN:
  9783433607145
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

Bad experiences with construction quality, the energy crises of 1973 and 1979, complaints about 'sick buildings', thermal, acoustical, visual and olfactory discomfort, the need for good air quality, the move towards more sustainability - all these have accelerated the development of a field that, for a long time, was hardly more than an academic exercise: building physics. The discipline embraces domains such as heat and mass transfer, building acoustics, lighting, indoor environmental quality and energy efficiency. In some countries, fire safety is also included. Through the application of physical knowledge and its combination with information coming from other disciplines, the field helps to understand the physical phenomena governing building parts, building envelope, whole building and built environment performance, although for the last the wording 'urban physics' is used. Building physics has a real impact on performance-based building design. This volume on 'Applied Building Physics' discusses the heat, air and moisture performance metrics that affect building design, construction and retrofitting.

1
Outdoor and Indoor Ambient Conditions

1.1 Overview

In building physics, the outdoor and indoor ambient conditions play a role comparable to the loads in structural engineering, which is why the term ‘ambient loads’ is often used. Their knowledge is essential to make correct design decisions. The components that shape them are:

Outdoors		Indoors
Air temperature (also called dry bulb temperature)	θe	Air temperature (also called dry bulb temperature)	θi
		Radiant temperature	θR
Relative humidity	ϕe	Relative humidity	ϕi
(Partial water) vapour pressure	pe	(Partial water) vapour pressure	pi
Solar radiation	ES
Under-cooling	qrL
Wind	vw	Air speed	v
Rain and snow	gr
Air pressure	Pa,e	Air pressure	Pa,i

In the paragraphs that follow, these components are discussed separately. Bear in mind though that the greater the decoupling between the outdoor and indoor temperatures, and sometimes the relative humidit...