FLIR i3 User Manual

part. At a certain height there is a neutral zone where the pressures on the inside and
outside are the same, see the figure on page 80. This differential pressure may be
described by the relationship:
Air pressure differential within the structure in PaΔp
9.81 m/s
2
g
Air density in kg/m
3
ρ
u
Thermodynamic air temperature outdoors in KT
u
Thermodynamic air temperature indoors in KT
i
Distance from the neutral zone in metersh
If ρ
u
= 1.29 kg/m
3
(density of air at a temperature of 273 K and ≈100 kPa), this pro-
duces:
With a difference of +25°C (+77°F) between the ambient internal and external tem-
peratures, the result is a differential pressure difference within the structure of about
1 Pa/m difference in height (= 3.28 Pa/ft.).
Publ. No. T559580 Rev. a486 – ENGLISH (EN) – November 17, 2010 79
16 – Introduction to building thermography

FLIR i3 Specifications

General

Infrared Resolution	60 x 60 pixels
Thermal Sensitivity	< 0.15°C
Temperature Range	-20°C to +250°C
Field of View	12.5° x 12.5°
Focus	Fixed
Battery Life	5 hours
Operating Temperature	-10°C to +50°C
Storage Temperature	-40°C to +70°C
Display	2.8 in color LCD
Weight	0.34 kg