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Nov/Dec 2004
Heads Up: Mini LEDs Help Firefighters Breathe
Easier
 Scott Health and Safety
(www.scotthealthsafety.com, Monroe, NC) manufactures and markets
self-contained breathing apparatus and other respiratory protection
equipment, thermal imaging cameras, and breathing air compressors as
well as portable and fixed gas detection instruments. Scott is
perhaps best known for its Air-Pak brand of self-contained breathing
apparatus used by firefighters and other first
responders.
And thanks to a new heads-up display firefighters
using the Scott systems are breathing easier. The new display
features the integration of LEDtronics' LEDs into the respiratory
protection features on Scott Health and Safety’s groundbreaking
Air-Pak NxG2 Self-Contained Breathing Apparatus (SCBA). Miniature
LEDs illuminate the Air-Pak’s Buddy System Indicators that enable
firefighters to keep tabs on each other while in hazardous
environments, and the Heads-Up-Display that shows the air level of
the SCBA to the firefighter.
A federal safety regulation
stipulates that a firefighter must have an unobstructed view of how
much air is in the SCBA’s cylinder. The 2002 Edition for NFPA 1981,
Standard on Open-Circuit Self-Contained Breathing Apparatus for Fire
and Emergency Services, was issued by the Standards Council on July
19, 2002, with an effective date of Aug. 8, 2002. SCBA manufactured
under the 2002 standard are required to have a “heads-up display”
(HUD) that will display visual alert signals for breathing air
cylinder content and for battery condition. The HUD will display a
visual alert signal for breathing air cylinder content when the
breathing air in the SCBA cylinder has reduced to 50 percent of
rated service content.
To comply with this standard, Scott
Health & Safety designed its HUD to mount onto their E-Z Flo II
Regulator. The regulator then attaches to the facemask, positioning
the gauge in the firefighter’s field of view. To light up the
Heads-Up-Display, Scott engineers selected LEDtronics' LEDs due to
reliability and brilliance.
LEDtronics Inc
(www.ledtronics.com, Torrance, CA) manufactures an array of LED
products ranging from discrete surface mount indicators to direct
incandescent replacement LED lamps and bulbs for applications such
as transportation, panel indication and decorative lighting. LEDs
come in visible (400-700 nanometers), infrared (830-940 nanometers)
and ultraviolet (370-410 nanometers) wavelengths.
After
studying Scott’s design and specifications, LEDtronics’ field
representatives recommended sunlight-visible surface mount LEDs
(SML10xx-TR).
The Little Light
LEDs are
getting brighter in all LED package sizes. This is due to better
understanding of substrate elements and improved materials being
used to develop the LEDs. The application for the LED light source
dictates the size of the LED to used. For example, on medical or
handheld devices such as cell phones to light up push buttons or
face plates smaller is better. On large displays like message signs
to LED street lights larger LEDs is better.
Measuring 0.118"
L x 0.057"W x 0.018"H, they fit the display’s space allotment on the
regulator, but most importantly, the LEDs are radiant and easily
seen in dense smoke. LEDs of different colors (green, yellow and
red) represent air volume levels: full, three-quarter, half and
one-quarter. Other factors contributing to the selection of the
SML10xx-TR Series are their sparing use of energy and their low
generation of heat.
In a battery-operated application such as
the Air-Pak NxG2, the low power consumption of the LEDs means that
the Heads-Up-Display can function for a prolonged period of time
without taxing the battery pack of the SCBA. LEDs could last for
days to months on a battery-powered source. A 5mm LED and smaller
use less than 20 mA of power. The cool operation of the LEDs is
significant due to the Heads-Up-Display’s proximity to the
firefighter's facemask.
While the Heads-Up-Display can only
be seen by an individual firefighter, the NxG2’s Buddy System
Indicators are visible to other firefighters. Two LEDs, one to each
side of the air cylinder, are positioned on the SCBA’s backframe.
When operating normally the LEDs emit an intense blue-green light;
however, if assistance is needed, the LEDs change to vivid yellow to
alert other firefighters.
With the application requiring a
multicolor-capable LED, LEDtronics proposed its standard
sunlight-visible 5mm RGB LED (DIS-1024). Scott Health and Safety was
pleased with the LED’s color and vividness, but thought that the LED
in its standard discrete form was too susceptible to damage.
LEDtronics worked with the Scott engineers and created a sturdy
housing for the LED.
 They attached a wire harness to the leads,
placed the LED inside a clear lens (LCD470W-CW), encapsulated it in
water-clear epoxy, and then secured the final assembly to the
backframe with a nut and lock washer. The collaborative effort
yielded a panel-mount LED (PNL-1147-001) of stunning brightness and
exceptional durability. Solid-state circuitry makes it resistant to
the incidental impacts and the harsh environments that firefighters
experience in the course of their work. Moreover, its piercing
luminosity serves as a high-profile Personal Alert Safety System
(PASS) indicator that makes it easier for firefighters to keep a
watchful eye on their colleagues.
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Buddy
System Indicators, Heads-Up-Display and other technologically
advanced features are sure to make the Air-Pak NxG2 the preferred
choice for self-contained breathing apparatus among firefighters for
years to come. Like the firefighters who pick Scott products because
of their time-tested performance and brand integrity, Scott Health
and Safety selected LEDtronics' LEDs for the brightness that makes
them visible in thick smoke; for the solid-state circuitry that
allows them to endure the punishment of fighting fires; and for the
reliability that equals that of the firefighters depending upon
them.
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