Intrinsically Safe Handheld VHF Radios Are Saving Lives
Intrinsically safe handheld VHF radios are the new kid in town when it comes to meeting the communication needs of workers in differing hazardous conditions. Some examples are oil rig workers, first responders, and anybody else performing duties in environments with volatile gases that may produce an explosion when the gas comes in contact with a spark produced by a conventional VHF radio. The danger of using cellular phones on offshore drilling rigs led the US Mineral Management Service (MMS) to release a National Safety alert recommending the use of intrinsically safe radios.
What exactly does it mean to be certified an "intrinsically safe" handheld VHF radio? Let's take a look.
The basic meaning of intrinsically safe is to be incapable of throwing even the smallest of sparks. All that it takes is a tiny electrical discharge to cause an explosion in an area of undetectable atmospheric volatile gas. The process of created an IS radio begins in the design phase. The government has charges one company, Factory Mutual, with the enforcement of codes set by the National electrical Code and National Fire Protection Agency. From the beginning of the manufacturing process, Factory Mutual monitors the production company ensuring that IS standards are being met. Printed circuit board layouts, building materials, and schematics are then reviewed and audited. The manufacturer then submits two radios and four batteries for inspection and testing. After approval and the beginning of production, Factory Mutual still periodically visits the factories at random to ensure continued astringent compliance to code standards.
Factory Mutual provides design standards that space out the wiring on the printed circuit board, thus mitigation the possibility of short-circuiting. Also a limited internal current and voltage flow is dictated. You see, all radios utilize power amplifiers that give off heat. In IS radios, this heat must be limited. Each potentially explosive chemical has a given temperature of ignition. The radios must never emit heat that exceeds these limits. There are also very strict standards of capacitance and inductance. The casing of the radio is also designed of material that is incapable of producing sparks through friction (as if by dropping or scraping the unit).
Differing IS Classifications:
Class I:
A: Acetylene
B: Hydrogen
C: Ethylene
D: Propane and Methane
Class II:
E: Conductive metal
F: Carbonaceous material
G: Grain dust and flour
Class III:
Ignitable fibers or "Flyings"
IS radios are approved for use where an explosive atmosphere is the norm, not the exception.
Non-Incendive Radios:
"Non-incendive" radios are so labeled to imply that electrical equipment is incapable of releasing sufficient thermal and/or electrical energy as to cause an explosion in an area where a volatile atmosphere is a matter of fault, and not the norm.
The batteries for IS radios must also be designed and manufactured to be intrinsically safe. These batteries are equipped with diode protection, meaning that a charge can only go into the battery; no electricity will flow back out. The possibility of short circuiting must be eliminated. Flow of current and heat produced from the battery must be limited as well.
The main point here is that intrinsically safe radios are not a product of chance. All steps in their creation is planned and dictated. Customers needs are explicitly met with optimal safety in mind. Firemen, oil rig workers, mine workers, refinery workers, elevator shaft specialists, and many other professionals need intrinsically safe radios for a variety of potentially catastrophic applications.
Icom America Inc. has released the Icom M88 IS HH VHF Radio. It is designed with toughness and waterproofing in mind from the beginning. It is an excellent choice for both land and sea applications. It has an optional waterproof microphone/speaker for hands free operation. The unit comes with a belt clip. Here are some of its other features:
- 22 programmable channels for land use
- Li-Ion battery for extra long battery life. Up to 20 hours of talk time
- 6-unit rapid charger optional
- Simple operation featuring 6 clearly labeled buttons on front panel
- Large, clear LCD with backlighting
- Backlit buttons for use in dark situations
- Auto WX scan and WX alert function (US version only)
- Instant change to channels 16 or 9
- Powerful 5W output
- 4-level battery indicator
- Self-check function for internal temperature monitoring
