Illinois State Police Forensic Laboratory

Location: Crest Hill, Illinois
Owner/Operator: The Illinois Division of Forensic Services (DFS)
Client: Shiner + Associates
Architect: RADA Architects

Vibration Isolation Design Challenges for an Illinois Crime Lab

This new state-of-the-art facility is intended to replace the older Joliet Forensic Science Laboratory and increase the availability and speed of forensic testing throughout the state, including DNA, firearm, and toxicology analysis, to help reduce backlogs.

The preliminary plans for this single-storey building, across from Stateville Correctional Center, revealed three distinct wings, each serving specialized functions and housing a variety of laboratory spaces.

Vibration Mitigation of Sensitive Instrumentation During Forensic Laboratory Design

From an acoustical perspective, the project presented a unique challenge: several laboratory areas were designated for highly sensitive instrumentation, requiring ultra-low vibration environments to ensure the accuracy and reliability of forensic analyses. The proximity to a high traffic road, the inclusion of a firing range, mechanical rooms, and a vehicle garage, as well as the anticipated movement of personnel and equipment, all contributed to the complexity of vibration control within the facility.

HGC’s Vibration Assessment Approach

HGC Noise Vibration Acoustics was contracted to undertake a comprehensive review of the architectural drawings and site context, focusing on both ground-borne and structure-borne sources of vibration. The assessment began with an analysis of the building’s layout:

• West Wing: This area was to house the firing range, firearms laboratory, forensic biology lab, latent prints lab, a mechanical room, offices, and the CSCS team vehicle garage. Of particular concern was the firearms microscope room, identified as one of three ultra-low vibration spaces due to its sensitive equipment.
• Center Wing: The center wing was to contain the toxicology lab, drug chemistry lab, evidence room, offices, a conference room, and the main lobby. Within this wing, the toxicology instrumentation lab and drug chemistry instrumentation lab were highlighted as ultra-low vibration rooms, each requiring stringent vibration criteria.
• East Wing: The east wing was to be dedicated to training and fitness rooms, a boiler room, and service spaces, which, while important, were less critical from a vibration perspective.

HGC paid particular attention to the laboratory areas closest to Division Street and the parking lot, recognizing these as the most vulnerable to ground-borne noise and vibration. The acoustical consultants also identified structure-borne sources such as rooftop air handling units, the vehicle garage, mechanical rooms, the firing range, and routine activities within the labs as potential contributors to vibration levels.

Lab Room Vibration Control Considerations

The vibration criteria for the lab spaces were established in consultation with the lab planner and referenced industry standards. The most sensitive rooms—the firearms microscope room, toxicology instrumentation lab, and drug chemistry instrumentation lab—were required to maintain vibration levels below 1,000 micro-inches per second, while other lab spaces were permitted up to 2,000 micro-inches per second.

To address these requirements, HGC Noise Vibration Acoustics recommended several key design strategies:

• Structural Solutions: Increasing the slab thickness in ultra-low vibration rooms to 2.5 times the standard, creating a structural discontinuity and greater inertia to resist vibration transmission. Expansion joints were specified between critical and non-critical slabs, as well as around column footings within sensitive spaces, to further isolate these areas.
• Site Planning: Avoiding speed bumps in the parking lot and locating garbage/recycling areas and generators as far from sensitive labs as possible to minimize ground-borne vibration.
• Mechanical Isolation: Detailing rooftop mechanical equipment for vibration isolation and considering resilient materials within the structure of the firing range to attenuate high-frequency vibrations.

HGC also drew on experience from similar projects, noting that vehicle impacts and waste handling can significantly affect vibration levels in sensitive areas. By integrating HGC’s recommendations into the design, the Illinois State Police Forensic Laboratory was enabled to deliver a stable and controlled environment for forensic analysis. The facility’s layout and vibration mitigation measures minimized the risk of equipment malfunction, supported adaptability for future upgrades, and reinforced the lab’s reputation for technical excellence. Early collaboration between the project team and HGC ensured that vibration mitigation considerations were prioritized, resulting in a facility that can meet the operational demands of modern forensic science.

Vibration Consulting Services Provided by HGC Noise Vibration Acoustics

• Review of architectural drawings and site context

• Identification and assessment of vibration risk factors in critical lab areas

• Development of vibration mitigation strategies for ultra-low vibration rooms

• Recommendations for slab thickness and expansion joint detailing

• Site planning for vibration-sensitive spaces

• Mechanical equipment isolation design

• Ongoing consultation with project stakeholders