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Cleanroom Ceiling Grid Structures and Ceiling Mounts

See Also Cleanroom Ceiling Grid Conversion System to turn an unclassified space into an ISO cleanroom.
Celing Grid
Ceiling grid accommodates (click for more information)
  A) HEPA Fan/Filter Units
  B) Fluorescent Lights
  C) Blank Panels (polypropylene, dissipative PVC or steel) and
  D) UV Sterilization Lights (with timer and motion sensor to prevent operation when room is occupied).
  E) Make-up air ductwork routes air to HVAC system for recirculation into ceiling plenum
All BioSafe® Cleanrooms feature a modular ceiling grid structure that accommodates HEPA fan/filter units (FFUs) and fluorescent lights to meet diverse cleanliness and lighting requirements. Power Distribution Modules allow easy connection of ceiling modules to 115 or 230VAC power. Ionizing Modules neutralize static charges for additional contamination control.

Ceiling plenum   Ceiling Grid
BioSafe® ceiling plenum with grid structure during installation   BioSafe® ceiling plenum with insulating foam panels on top ceiling

Double-Wall Ceiling Plenum

A double-wall ceiling structure, standard on most BioSafe® Cleanrooms, allows cooled make-up air to be recirculated into a plenum chamber, which feeds the fan/filter units (FFUs) positioned on the lower ceiling, directly above the controlled environment. This design eliminates the need for individual make-up air ducts to be installed for each FFU and simplifies air balancing since all FFUs draw from a common air source.

In this design, return air is pulled from the cleanroom panels into return ducts installed along the ceiling. In applications requiring containment of potential biohazards, high-volume air handlers can be installed in the ceiling plenum to draw enough air out of the cleanroom to create a negative air pressure (see BioSafe® Cleanroom HVAC and Air Control for more information on air handling and balancing).

The double-ceiling plenum is fabricated of interlocking powder-coated steel joists, creating a rigid T-bar structure that requires no suspension cables or other external supports. Although not intended to be a walkable surface, the ceiling provides ample strength to support spans of up to 24 feet (7315 mm), even when loaded to capacity with FFUs.

The ceiling plenum typically operates under negative air pressure with respect to controlled cleanrooms below it. This ensures that particles inside the plenum are not pulled through cracks or other breaches into the cleanroom. Blank ceiling panels, made of 3/8" (9.5 mm)-thick polypropylene, are heavy enough to maintain a seal despite the negative pressure inside the ceiling plenum, which tends to lift lighter-weight panels.

All ceiling modules, which also include FFUs and lights as well as blank panels, rest in the T-bar grid supports along the openings created by the grid structure. Typically, these bays are 24" x 48" (610 mm x 1219 mm), although some cleanroom designs require 24" x 36" (610 mm x 914 mm) or 24" x 24" (610 mm x 610 mm) bays. Ceiling clips installed along the perimeter of the T-grid firmly hold these drop-in modules in place to prevent particle influx from the ceiling plenum, even under internal pressure.

HEPA Fan/Filter Unit (FFU): 24" x 48" (610 mm x 1219 mm) model shown, 24" x 36" and 24" x 24" (610 mm x 914 and 610 mm x 610 mm) models also available

Fan/Filter Units (FFUs)

Fan/Filter Units provide the vertical flow of filtered air that creates a clean environment.

Each FFU consists of a 3-speed motorized impeller fan, which provides an average of 650 CFM, cubic feet per minute, (1105 m³/hr) of air moving at a speed of between 80 and 90 feet per minute (.41 and .46 m/s), on medium speed. Before it exits the FFU, this air passes through a High Efficiency Particular Air (HEPA) filter that removes 99.99% of all particles ≥0.3 microns in diameter. Airflow baffles inside the FFU ensure uniform air speed across the filter face, and sound-deadening foam reduces noise and vibration. Each FFU generates less than 50 dBA measured 30" (762 mm) from the filter face at high speed.

Related Pages:

HEPA FFUs Cat. #
23.625" x 47.625" x 12.5"H (600 mm x 1210 mm x 318 mm),
for use in 24" x 48" (610 mm x 1219 mm) ceiling bays

Fluorescent light   Teardrop fluorescent light
Fluorescent light for 24" x 48" (610 mm x 1219 mm) grid space
(No. 3800-80)
  “Teardrop" fluorescent light installed between 24" x 48" (610 mm x 1219 mm) grid space occupied by FFUs (No. 6704-15)

Fluorescent Lights

Terra offers several ceiling lights to ensure ample cleanroom illumination and accommodate all cleanliness requirements.

2' x 4' (610 mm x 1219 mm) Light Module   Cat. # 3800-80
This painted steel housing includes four T8 fluorescent tubes, providing 9440 lumens. Each module occupies a standard 2-foot by 4-foot (610 mm x 1219 mm) bay in the ceiling grid.
Teardrop Light   Cat. # 6704-15A
Ideal for cleaner-than-Class 100 (ISO 5) rooms in near-100% FFU coverage leaves no room for standard lights, these modules attach to the T-grid supports between ceiling bays. Their aerodynamic design ensures minimal interference of laminar airflow. Dimensions: 48"L x 2"D x 6"H (1219 mm x 51 mm x 152 mm). Intensity: 3150 lumens.
Flow-Through Light Module   Cat. # 6704-77
Low-profile fluorescent-tube module stacks beneath a 2' x 4' (610 mm x 1219 mm) FFU. Adds 4.75" (121 mm) to the ceiling height. Intensity: 8560 lumens. Must be ordered together with FFU.

Recommended lighting configurations.

Power Distribution Module   Power Distribution Module covers removed
Power Distribution Module covers removed (ceiling mount on left, panel mount on right)
Night Service Switch
  • Energy-saving mode saves 25% of fan operating costs by reducing power consumption during off-hours
  • Maintains round-the-clock cleanroom integrity at lower cost
  • Easy to activate via panel-mounted switch (Wireless Cleanroom Control System also available)

Why Pay More for Less?
Terra cleanrooms are designed to meet a specified ISO cleanliness rating when a cleanroom is in use: with operations in progress, process machinery humming, and personnel in motion. So why pay to maintain that level of FFU performance when a production shift ends and people, the greatest source of contamination, leave the room?

With a greatly reduced contaminant load, a cleanroom at rest maintains its target ISO cleanliness standard with much less airflow, fewer air changes—and decreased power consumption. Terra’s Night Service Switch provides this cleanliness at a nominal cost, giving you immediate cost savings.

Simply select the “Night Service” Switch when you turn off the lights and go home. A separate operation circuit drops all Fan/Filter Units (FFUs) into low-energy operation mode, shaving 25% of energy costs off your power bill while maintaining uninterrupted cleanroom performance at your specified cleanliness level. With Terra's Night Service Switch, operators can save up to 7,000 kilowatt-hours per year with a return on investment in slightly over a year.**
Ordering Information
A complete system includes fan/filter units and Terra's standard Power Distribution Modules (order separately), in addition to the units specified below. The Night Service Switch includes electronic configuration of each FFU controlled by this system. The Control Panel includes switch settings and indicator lights for Normal Mode and Night Service Mode, as well as a tamper-resistant master FFU Off switch.
Night Service Switch
Order one per Fan Filter Unit Cat. # Price
120VAC, 60Hz 6601-70 $ 120
Control Panel for Night Service Switch
Order one per cleanroom 120VAC, 60Hz 220VAC, 60Hz
Cat. # Price Cat. # Price
BioSafe All-Steel Cleanroom 6600-26-NS $ 2,039 6600-26-NS-220 $ 2,039
Comparative Specifications:
2' x 4' (600 x 1210 mm) Terra Fan/Filter Unit No. 6601-24-H, operating at High, Medium, and Night Service setting
Operation Setting: High Speed* Medium Speed* Night Service
Airflow: cfm (m^3/hr) 808 (1373) 717 (1218) 654 CFM (1111)
Air Speed: ft/m (m/s) 115 (.58) 102 (.51) 93 ft/min (.47)
Run Amps (Watts): 4.3 (512) 3.5 (416) 3.3A (393W)*
*25% savings over operation on high speed
**Based off of an average-sized cleanroom with 10 FFU's, active cleanroom usage of 8 hours per day, and the U.S. Energy Information Administration's given average retail price of electricity at 10.72 cents per kilowatt-hour.
Electrical panel
Electrical panel, installed in service corridor, gives easy access to serviceable electrical components (all UL-listed breakers, transformers, relays, switches) and provides a single power connection for the entire cleanroom

Power Distribution Modules (PDMs)

Thee modules dramatically simplify connection of ceiling FFUs and lights and allow operation from a single Control Panel. Each accommodates up to 5 FFUs and 5 lights and includes a step-down transformer for low-voltage control and operation of status indicator circuits (Control Panel below). Includes relays and circuit breakers for overload protection of all connected devices, AC contactors, and NEC-compliant quick-connect fitting for lights and FFUs. Includes installation on specified Terra cleanroom.

For Multiple Power Connection Points
Each module must be wired to a dedicated 24A fused 120 or 240VAC circuit.
View Configuration

Cat. # Price
6600-29B-P $ 1,614
6600-29B-P-220 $ 1,614

FFU control module
EnergySaver™ FFU Control simplifies air balancing and reduces energy costs

EnergySaver Filter/Fan Unit Control

This programmable unit lets you adjust FFU operation levels, either individually or on a room-by-room “cluster” basis. This remote operation lets you balance air pressure and cleanliness levels in multiple-room configurations to meet specified cleanliness levels, simplifying final testing and certification of your facility.

A “Not in Use” setting maintains desired cleanliness levels at a lower fan speed when rooms are not occupied, saving energy expenses and cutting heat generation. Passcodes ensure security.

Complete specifications and ordering information.

Ionizing Bar
Ionizing bars enhance static and contamination control by eliminating surface charges that attract particles

Ionizing Bars

Ionizing bars use intrinsically safe low-voltage (24V) circuits to generate balanced streams of positive and negative ions, which neutralize static charges. Each bar is mounted beneath an FFU, so that the vertical airflow distributes ions throughout the cleanroom.

By neutralizing charges, ionizing bars protect static-sensitive parts against electro-static discharge (ESD), which can degrade or destroy sensitive electronics. They also eliminate charges surfaces that can attract and hold particles, resulting in a cleaner work environment.

Complete specifications and ordering information.

Control Panel   Status indicator
Control panel includes switches for lights and FFUs, along with a Magnehelic® Differential Pressure Gauge to monitor room air pressure (shown above with additional switch for optional UV lights)   Operation Status Indicators, included as part of control panel system, glow to indicate FFUs are operational, flash when FFUs are turned off
Control Panel with Operation Status Indication (OSI)   Cat. # 6600-26
Mounted outside each cleanroom, this panel allows convenient operation of FFUs, lights, ionizing modules, and other environmental monitoring equipment selected for your BioSafe®facility. Fabricated of 304/316L stainless or powder-coated steel to match your cleanroom, it includes a Magnehelic® Gauge (-.25 – 0 – .25"WC) that displays room differential air pressure.

This system also includes top corner indication lights that display cleanroom operation status: lights glow when FFUs are in operation and flash to indicate they are off.

Related BioSafe® Pages

BioSafe® Panels: Pre-engineered, modular structures provide smooth, easy clean surfaces
Multi-Room Configurations: internal walls, antechambers, corridors
HVAC and Air Control: including ceiling plenum and ducting system
CleanZone™ Powder Containment Modules: create a pharmaceutical powder containment room
BioSafe® Cleanroom Accessories: power and gas connections, sterilization modules, humidity controls and fire safety solutions.
BioSafe® Pass-Throughs and Air Showers: a complete line of interlocked chambers that prevent contamination during personnel or material transfer
Installation and Certification Services: include 3rd party validation of cleanliness rating, filter integrity, and pressure levels
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