Shielded facilities present an electromagnetic barrier to the outside world. The purpose of the shielding could be to keep sensitive information inside the facility, or it could be to keep outside sources of radiation from affecting measurements made inside the facility. And for many users, both of these are important requirements.
The Howland Company has been involved in numerous projects of this kind. In some cases only portions of a facility were shielded, while in others the shield was actually integrated into the structure of the building itself.
Here are a few examples:
Primary Standards Lab, US Dept of Energy,
Sandia National Labs