Estimated between $120 and $140 million USD per year, the North American confined space gas detector market is very large, and very mature. Many confined space instrument users are on their fourth or fifth generation of gas detectors and seem to be as knowledgeable about the instruments as the product manufacturers themselves.

Because of the market's size, the competition between confined space gas detection product manufacturers is fierce, which has led to increasingly good deals in terms of features and price for end-user customers. With every new generation of product comes even better features and capabilities, at ever lower prices.

Let's look at some of the trends and changes that are occurring in the confined space gas detection market and that are benefiting end-users.

1) Prices, sizes dropping

According to industry consultant Frost & Sullivan's "U.S. Market for Air Emission Monitors and Analyzers," in 1996 a typical four-sensor confined space gas detector cost the purchaser around $2,500 USD. Today's gas detection customers get far better features and capabilities at a fraction of the previous cost. Most leading manufacturers now offer high-quality, basic four-channel (LEL / O2 / CO / H2S) confined space instruments starting at $695 to $995 USD. In many cases, the cost of a brand new four-channel confined space instrument is less than the cost of replacing the sensors and battery pack in an existing instrument bought only two or three years previously.

This fact has many customers rethinking the management of their inventory of confined space instruments and has led to shorter product life-cycles. Instead of keeping their detectors for five or six years as in the past, many customers now trade them in after only two or three years to take advantage of design improvements and lower prices.

Confined space gas detectors are getting smaller, easier to use and increasingly durable.

2) Physical durability

The increasingly rigorous testing necessary to achieve UL, CSA, and EEx European Community (ATEX) Classification for Intrinsic Safety has led to dramatic improvements in physical durability of confined space instrument designs. Instrument housings frequently include built-in soft or cushioning elements to absorb the energy when the instrument is dropped.

The drop tests required as part of the Intrinsic Safety Classification process have led to designs that can readily survive being dropped from all angles from a height of at least two meters onto a cement floor. The CE Mark necessary to sell instruments into the European market requires the demonstrated ability to withstand bombardment with radio frequency interference (RFI) and electromagnetic interference (EMI) that would have rendered many instruments manufactured just a few years ago inoperative.

3) Longer battery life

Improvements in rechargeable battery technology enable instruments to run much longer on a single charge, while the batteries themselves last for many more charging cycles and are difficult to damage either by overcharging or by allowing them to become completely discharged. In the past, failure to exercise or periodically discharge nickel cadmium (NiCd) rechargeable batteries could easily lead to a loss of capacity, or what was commonly referred to as developing a "memory." Today's "smart" chargers include microprocessors that automatically avoid damage due to overcharging by dropping the charging current to a trickle the moment charging is complete.

Newer types of rechargeable batteries such as nickel metal hydride (NiMH) or lithium-ion batteries are inherently harder to damage, and are capable of storing much more energy in a much smaller volume. Use of lower power sensors, more efficient instrument electronics, and the new battery technology has resulted in run times of 18 to 20 hours or even longer for many confined space instruments. At the same time, since the new batteries store much more charge per unit volume, the size of the instrument is actually reduced.

4) Datalogging more common

Datalogging is no longer an exotic feature used only by "experts." Most confined space instrument manufacturers now include datalogging on a standard basis, or for a minimal additional cost. Even when customers do not use the feature on a regular basis, automatic datalogging is increasingly popular as a "black box" method of verifying proper use of the instrument, or reconstructing the conditions experienced during an emergency.

Some instruments are now capable of storing up to a year's worth of monitoring and calibration data at a time in the instrument's on-board memory. Datalogging is totally transparent to the instrument user, but the information is available should the need ever arise.

5) Docking stations

"Docking" stations that include fully automatic calibration, datalogging download and charging are redefining the way that customers with large numbers of confined space instruments deal with maintenance and calibration issues, making CS instruments easier to use and maintain. Instead of technicians or instrument specialists laboriously calibrating instruments one at a time, docking stations allow end-users to simply drop the instrument into the calibration station and the station automatically calibrates and updates the records for the instrument.

6) New sensors

New sensor technologies such as miniaturized photoionization detectors (PIDs) for volatile organic contaminant (VOC) measurement, non-dispersive infrared (NDIR) sensors for CO2 or combustible gas, and additional types of substance-specific electrochemical sensors are all available for incorporation into confined space instruments. As exposure limits continue to drop, confined space programs increasingly need to include direct quantifiable measurement for many additional toxic substances.

SIDEBAR: Instruments taking on dual roles

For many instrument users, the role of confined space gas detectors is expanding to include a variety of non-confined space activities.

A fire department, for example, might use the same instrument both for confined space rescue as well as for general hazmat response. Compact four-channel confined space gas detectors are increasingly used as personal monitors for workers at refineries, chemical plants or oil platforms subject to the potential presence of dangerous atmospheric conditions.

In the past, personnel at these facilities might have used colorimetric tubes or a single-sensor H2S detector to verify that atmospheric conditions were safe. Use of multi-sensor detectors means that workers are immediately aware of combustible as well as toxic gas releases or accumulations.