Case Study: North Fraser Pretrial Centre

About This Project

Opened in 2001, the North Fraser Pretrial Centre is a maximum security facility with a “podular” layout: Each pod has four living areas encircled by 30 two-bunk cells. Staff run operations from elevated control centres.

The podular design allows inmates to access programs and services in the living unit itself, rather than a central location. This reduces prisoner movement through the facility, which in turn improves security and safety for both staff and inmates.

SCOPE OF SERVICES

We worked on the original design with DGBK Architects, consulting on the acoustical design to control reverberation and improve speech intelligibility in common areas. We also made recommendations for sound isolation between cells and to control noise from HVAC systems.

We had to select acoustical treatment that would satisfy security requirements and provide good acoustics, which benefit inmates and enable guards to communicate effectively in emergency situations.

In 2010, we were hired to assess sound isolation between the video conferencing rooms and visiting rooms. We visited the site and tested the sound isolation performance of key separating partitions. After analyzing the results, we provided detailed findings that specified the Noise Isolation Class (NIC) rating of each partition.

Noise Isolation Class (NIC) rates how well a separating partition limits airborne noise transfer in the real world. In comparison, Sound Transmission Class (STC), another common acoustical metric, quantifies laboratory testing of partition assemblies.

Acoustical Challenges

At the North Fraser Pretrial Centre, our tests found that all three partitions fell short of typical NIC ratings of similar walls.

We also identified details that were affecting acoustical privacy in these rooms. For example, our acoustician noted missing acoustical gaskets between doors and frames, and non-laminated single-pane glass on door panels and windows. Where acoustical gasket was present, the acoustician found that it was installed incorrectly.

PROJECT BENEFITS

After testing the rooms, we provided detailed recommendations to improve speech privacy for each room—offering specifications for both standard levels and high levels of privacy. If the latter were achieved, normal speech would be almost inaudible in adjacent spaces.

We also included information about selecting the door seals, window lamination, and other upgrades necessary to achieve each privacy level.

By providing real-world analysis and clear, detailed paths to achieving two different outcomes, we ensured that the client had the information they needed to improve the acoustical privacy of the visiting rooms and video conferencing rooms.