Negative Pressure Rooms
CBRNe threat containment for ASAP III mail screening systems
Negative Pressure Rooms (NPRs) are air-tight enclosures used to house dangerous human-intensive inspection processes. Many such rooms are currently being used for front-end postal operations in government departments and high-profile private businesses.
The negative pressure room is driven by powerful fans under the perforated downdraft table surface which pull potential threats away from personnel while also drawing in and circulating HEPA-filtered fresh air.
Research International offers both standard and custom examination rooms and mail screening monitoring equipment to prevent such incidents.
Request a QuoteKeeping Staff and Workplace Safe from CBRNe Threats
Protect Employees on the Front Line
A white powder or other mail room CBRNe incident can be life-threatening. Keep your staff safe from threats like anthrax and ricin.
Avoid Costly Building Closures and Cleanup
A CBRN contamination incident can mean long-term facility closure, and cleanup can cost millions. A negative pressure room contains the threat.
Suitable for Fixed or Mobile Installations
Each NPR is designed to meet your requirements and fit your budget. Short on space? Your NPR can also be installed in a trailer.
- Features
- Applications
- Operational Details
Features
Typical Product Features
Each negative pressure room is custom-designed for the unique needs and budget of our customers. Features may include some or all of the following options:
- Downdraft table with HEPA and VOC filtration
- Clear polycarbonate panel walls for visibility
- Lighted exit sign
- Fingerprint scanners at entry doors
- Heavy duty doors with magnetic locks to maintain pressure
- Intake manifold for delivering sampled air to detectors
- Heavy duty mail jogger
- Box probe for inspecting packages
- Wall-mounted Magnehelic pressure meter
- Cabinets for detection equipment
Applications
Applications
- Government and corporate mail rooms
- Customs inspection
- Border crossings
- Handling and packaging of known toxic materials
Operational Details
Operational Details
Negative pressure rooms provide a controlled environment for inspection operations and generally include one or more D1000 downdraft table and various CBRNE monitoring devices such as the ASAP III or ASAP V, depending on the customer’s threat profile.In this way many types of dangerous substances that may come in with postal or other items are identified and contained before being released into a governmental or business work area where many lives might be lost and/or costly infrastructure damaged.

polycarbonate and extruded aluminum construction.
NPRs are typically constructed of light-weight aluminum extrusions and transparent high-strength polycarbonate plastic (Figure 1). Use of a transparent wall material minimizes claustrophobia of workers inside the room, and allows visual surveillance of room operations from outside the room. The rooms operate slightly below ambient atmospheric pressure. Incoming and exhaust air for the rooms are both filtered through high-efficiency HEPA filters and access is often through air lock-style doors, making the environment within the rooms similar to that in an electronic or pharmaceutical clean room. Workers with allergies find that working in the rooms greatly relieves breathing problems.
Negative pressure rooms provide a controlled environment for postal operations and generally include one or more D1000 downdraft tables and various CBRNE monitoring devices such as the ASAP III or ASAP V, depending on the customer’s threat profile. In this way, many types of dangerous substances that may come in with postal items are identified and contained before being released into a governmental or business work area where many lives might be lost and/or costly infrastructure damaged.

The NPR's environmental control system utilizes proven HEPA filtration technology for particulate control and carbon/zeolite filtration technology for chemical gas control. The HEPA filters employed have an efficiency of 99.97% or better for any particle greater than 0.3 microns in size. By way of comparison, a single anthrax spore is from 1.0 to 1.5 microns in diameter.
Fresh air is injected into the room from roof-mounted fixtures, creating downdraft conditions within the room (see Figure 2). The source may be either ambient air or recycled NPR air that has been thoroughly filtered and cooled. Depending on the size of the NPR, it is fitted with a number of these filtered downdraft air injection vents. Air handlers with HEPA discharge filters are used to remove air from the room. A typical system completely changes the air once every minute. In comparison, United States OSHA standards for smoking lounges require only 60 CFM per person – a rate nearly ten times less than an NPR.
It is generally possible to couple the exterior air handlers discharging air from the NPR with the D1000 downdraft tables so that each exhaust filter ensemble contains a foam large-debris prefilter, two HEPA elements in series, and an activated carbon/zeolite filter as in Figure 3.
As discussed, the NPR’s conditioned air system provides a flood of clean air from the ceiling while removing potentially contaminated air by evacuating it through blower-powered air handlers. Air is filtered as it enters the room from the ceiling and then filtered twice more as it leaves the room. The system is deliberately redundant to provide maximum safety to employees both in the room and outside the room. Filtered air discharged from the room is so clean that it has been reported by representatives at a major oil company that since installing and using their NPR, the company has found a significant reduction in particulate count for the entire floor of their Houston, Texas headquarters.

If there is no space for the negative pressure room inside the building, the fully-functioning NPR can be installed in a trailer (see Figure 4). This has the added advantage of mobility for organizations that may have more than one location to service.

For further information on a negative pressure room for your application, contact us at info@resrchintl.com or 1-800-927-7831.
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