Can infrared waves pass through walls

I remember reading that infrared cameras can be used to help find people trapped in collapsed buildings which suggests they can, but then I keep finding stuff such as the following that says the opposite.

http://answers.google.com/answers/thread…

"An IR Remote Control will not pass through objects such as wood and
metal. It will go through some glass and not others because not all
glass is transparent to infra-red (IR) light."

http://cictr.ee.psu.edu/CICTRnews/Wirele…

"Another drawback is that infrared signals cannot pass through walls or ceilings"

Unless some infrared waves can pass through walls, and others cant, how is this explained?

A couple of points
1) the wavelengths for remote controls , IR comms etc is about 1um, which is
very close to visible light and thus is similarly affected by obstacles.

2) The thermal imaging of animals/houses etc is done at longer wavelengths (about 10-15um)
due the black body radiation peaks being at longer wavelengths. It still can't pass through
significant obstacles but will pass through smoke.

3) Under fallen debris you are relying on conductive heat transfer from a body to the
debris locally raising the temperature of the debris allowing IR radiation from the debris
to be identified as a possible survivor