Hazardous Operations: A Primer on In-Suit Communication Options

Trying to communicate while inside a hazmat suit can be a real hassle, especially if you are using a conventional PTT (push-to-talk) handheld microphone.

To address this problem, equipment manufacturers have come up with clever solutions for protective suit wearers. These products solve the “can’t shout through the mask” issue and make radio activation easy to execute.

What follows is an overview of basic product options for in-suit communications, to give you a sense of what’s out there on the market. Then, to aid you in your buying decisions, we’ve supplied a number of “must-answer” questions for you to consider.

In-Suit Microphones

For most protective-suit wearers, their radio microphone is their link to the outside world. This is why it’s vital for the microphone to be reliable, rugged and easily accessible. So what do you do when your face is encased by either a soft or hard plastic mask? The answer is some form of hands-free in-suit solution, such as a boom, throat or bone-inductive (“bone”) microphone.

The boom microphone is the most common hands-free solution for two-way radio communications. Typically, a “boom mic” is mounted to a set of headphones/ear protectors, an over-the-head metal band or an in-earplug. Just place the mic in front of your face, put on your face mask and you’re good to go.

Motorola, OTTO Communications, RadioMate, and Television Equipment Associates (TEA) are among the many manufacturers who sell boom microphone solutions.

Motorola and OTTO offer heavy-duty and lightweight headset, behind-the-head and earpiece boom products. OTTO’s Hurricane behind-the-head unit combines noise-reduction earphones with an extremely thin, small profile that fits easily inside a protective headpiece.

The RadioMate RMT 312 is a truly lightweight boom microphone system. The boom itself is attached to a stretchable soft headband, which slips on and off easily. Meanwhile, audio is carried to the user via a small earpiece.

TEA’s LITE II boom headset is specifically designed for use under gas masks. It comes in either single or dual earphone configurations, is weatherproof and can operate in temperatures as low as -20º F. If you expect to be in water, a special version of TEA’s TASC-I boom headset is submersible up to 66 feet.

A throat microphone consists of a small microphone embedded inside a flexible strap. This strap is worn around the user’s neck. It picks up the vibrations inside the user’s throat as he speaks, translating and then relaying them into the radio as sound. The advantage of the throat mic is that, since it is not dependent on actual sound waves, it is oblivious to background noise.

CON-SPACE Communications’ SR65i is a combined throat microphone and chest-activated button system. “It has a huge PTT switch that is easy to press in the most difficult working situations,” says CON-SPACE spokesperson Allan Lanzador. “Our equipment is also engineered to produce no electricity leakage, so that it can be used safely in highly explosive environments.”

OTTO’s Tactical Throat Microphone (TTM) comes with an earphone, an acoustical tube and a chest-mounted PTT activation button. According to the company website, it is “sensitive enough to pick up even a whisper.”

The bone microphone works much the same way as the throat mic, insofar as it captures vibrations generated inside the user’s head and sends them into their radio as sound waves. However, the bone microphone picks up vibrations “induced” into the user’s skull as they speak. Typically, the microphone for bone-inductive equipment is built into the user’s earpiece. This minimizes the amount of weight they are carrying on their head, and makes for an easier fit inside helmets. Like the throat mic, the bone mic doesn’t pick up background noise.

TEA’s Invisio Bone-Mic Headset is one of the smallest bone-induction headsets on the market. Basically, all you have to deal with is an earphone and a wire, because the Invisio’s vibration microphone system is built into the earpiece. The Invisio’s cable is shielded in Kevlar/Teflon-insulated polyurethane with “break performance of 100 pounds,” says the company’s website. “You can don and doff any gas mask without disturbing radio comms.”

Rather than fitting inside the ear, OTTO Communications’ Skull Microphone System (SMS) features a flexible rubber “X” that sits on top of the user’s head. The SMS comes with a rubber cup earpiece that blocks out exterior noise, and a chest-mounted PTT activation button.

Motorola and Earmark both carry interesting variations on in-suit microphones. Like a conventional microphone, Motorola’s CommPort system works by picking up sound waves emitted by a person’s speech. However, it doesn’t use a boom to do so. Instead, a tiny microphone is integrated into the user’s earpiece, picking up the sound waves as they cross the speaker’s face.

“We’ve tested the CommPort in thousands of hazmat suit applications,” says Nick Gandotti, an accessory and energy parts manager with Motorola. “It provides the kind of voice quality found with conventional boom mics, but fits nicely inside a protective mask.”

Meanwhile, Earmark’s Surface Adhering Microphone (SAM) is an external mic that adheres to the outside of a mask, picking up the air vibrations of the person speaking inside. The beauty of this solution is that it minimizes the amount of equipment inside the mask. The downside is that the SAM, although firmly adhered, is vulnerable to being knocked off.

Radio Activation Systems

Solving the microphone dilemma is only one part of the in-suit communications challenge. The next one is how to activate the radio without fumbling for a hard-to-find button.

One approach that has been adapted from SWAT/surveillance radio systems is the handheld PTT button. Typically, the PTT button is hard-wired along the user’s coat sleeve and run down to their thumb. When they need to talk, they just push down their thumb and the system does the rest.

Unfortunately, push buttons may not be practical when you are wearing heavy gloves or if you have your hands full.

A variation on the push button is the chest-mounted activator. Basically, this is a large button that is worn on the outside of the user’s coat, or indeed anywhere else that they find both accessible yet out of the way. The advantage of the “chest button” is that its size makes it easy to hit without precision—just thump your chest and talk. The disadvantage is that you have to wire it to the outside of your suit, which can compromise its integrity. You could wear it under your clothing, but this might make it harder to depress the button enough to activate the radio.

RadioMate’s RMT XX2-F Body Push-to-Talk Button is specifically designed to be worn under hazmat suits, says the company’s website, while the RMT-XX2-1 is a pistol-grip hand-activation switch that can be used when wearing gloves.

Motorola makes a wide range of PTT chest-mounted buttons, from large versions for protective suit wearers to small buttons for bicycle police. TEA also makes PTT switches that range from chest-mounted to thumb and ring-finger mounted buttons.

A third option is voice activation; you tell your radio to open a channel, and it does. For a suit wearer, voice activation is the ultimate hands-free alternative. However, some users might be concerned that the radio could be triggered accidentally if the user trips and yells. In turn, a system failure could leave the user with no way to activate their radio in an emergency. For this reason, a physically activated backup is worth considering as well.

“Motorola’s voice-activated system lets you verbally command your radio to open and close channels,” says Gandotti. “You can also combine it with a body-mounted PTT, for those instances when voice activation could be difficult due to noise or other factors.”

Specialized Radios

In general, most portable radios resemble brick-shaped walkie-talkies. However, there are some companies that make specialized radios that might be a better choice for suit wearers.

A case in point is the Earmark VOXSET II, which has the radio unit integrated into the user’s headset. The upside of this unit is that everything sits on the user’s head, eliminating the need to tote a portable or to string wires through the suit. The downside is that VOXSET II sits on the user’s head, adding weight and bulk inside the facemask. Plus, the VOXSET II operates in the 72–76 MHz range; to use it in tandem with standard VHF/UHF radio systems, you will need some kind of frequency conversion device in your radio network—most likely on the truck.

Icom America’s new IC-F50 handheld is “fully submersible,” says Jim Smith, Icom America’s government sales manager. Specifically, the IC-F50 has been proven to operate after being submerged in three feet of water for half an hour. So how does this apply to in-suit radio communications? Answer: If your portable radio is this tough, it’s one less thing to worry about.

Choosing the System That’s Right For You

There is no one-size-fits-all solution to choosing the right system. Instead, there are a series of questions you need to answer on behalf of your users, in order to make the best choice.

How often do we use in-suit communications?

If your department rarely suits up, it makes little sense to equip everyone with skull-mounted, voice-activated radios. Instead, you might want to have a few in-suit units on hand in each truck, or you may prefer to create special hazmat response trucks that are fully-equipped with in-suit radio equipment.

In turn, if your department expects to be dealing with a lot of hazmat calls—whether due to possible terrorist biological/chemical attacks or just industrial activity in your territory—then you might want to make suiting up a regular part of your staff’s daily routine. If so, investing in skull and/or throat mics could make sense. A compromise would be boom, bone induction or CommPort-style microphones.

What audio qualities are most important?

The purpose of any radio system is communication. However, deciding what elements of communication matter most is often a judgment call.

For instance: If accurate voice reproduction is a top priority for you, then a conventional microphone product—with or without boom—might be the best choice. However, if background audio keeps drowning out your people, you should consider bone-induction or throat microphone solutions. Because these products rely on actual physical vibrations from the user’s body, they don’t pick up ambient noise.

One caveat: Using a vibration system will make it impossible for someone else to just “grab the mic” and talk. Instead, they’ll have to take the bone/skull/throat harness off the user and put it onto themselves before you’ll be able to hear them. If you choose to rely on a vibration system, you might want to consider having a few officers equipped with conventional PTT portables for situations to resolve this situation.

Which systems set up fastest?

Time is always an issue when it comes to protective suits; generally, the sooner your people can get them on and get to work, the better. This is why it makes sense to get a full range of product samples before you choose one system over another, to see how easily each one can be deployed during an emergency. This said, speed isn’t the only issue; performance also counts. But that’s the point of testing: seeing how each product solution performs under actual conditions in all aspects, so that you can make the best buying decision.

What are the parameters in our area?

Before you buy, it is critically important to cross-reference the specifications for each product that you are evaluating. Can they all perform within the same range of extremes? Are certain solutions less rugged than others? If so, does this difference really matter: Will your people be operating in the extremes covered by the most rugged products, or will they be working within the parameters covered by them all? Again, you need to know this answer before choosing an in-suit communication system, because you don’t want to disqualify an otherwise-ideal choice on the basis of specs that don’t actually matter or disregard those that do.

The problems of range suffered by the Fire Department of New York’s digital radio system—problems that were all too apparent during 9/11—underscore the importance of field-testing new equipment before deployment. In the case of in-suit communications, this means obtaining or even buying samples of the different systems and testing them before your department signs a purchase order. Once you have these samples, put them through the wringer. You need to base your decisions on your department’s own experiences, not the marketing materials of the manufacturers.

Conclusion

There are many options available for in-suit radio communications. Moreover, each one has its own advantages and disadvantages: Choosing the right system for your department demands careful research and field-testing.

In a world where industries work with a toxic soup of chemicals, and terrorists have already released the nerve gas sarin in a Toyko subway, protective suits are an unavoidable fact of first responder life. This is why, whatever in-suit communications system your department eventually chooses, the time to start weighing the options is now. The lives of the people in your department and the public they protect every day are too valuable to do otherwise.