BAGHDAD: The Humvee’s air conditioner conked out right after four US soldiers clambered aboard for a run through some of Baghdad’s most dangerous streets. The temperature was 46 degree Centigrade — and without AC, it would quickly rise to 66 degree Centigrade or higher inside the vehicle.

So 1st Lt. Robert Plummer and his men took the lesser of two unpleasant choices: They got out and walked.

“If you’re out walking around, there’s not much you can do but sweat a lot, wearing 36 kilograms of gear,” said Plummer, a 31-year-old man with the 12th Infantry Regiment.

As the US military spends its fifth blistering summer in Iraq, the Army is evaluating new garments to help fight the dangerous combination of extreme heat and the heavy protection needed in the battlefield.

Cooler soldiers “carry out their mission longer. They’re less likely to make mistakes because they’re mentally more alert,” said Walter Teal, an engineer at an Army lab in Natick, Massachusetts, where some of the heat-busting concepts are designed and tested.

The research has been built around a simple idea: vests that cool soldiers. But at the blazing summer temperatures in Iraq, it becomes a rather complicated issue of weight versus reward.

The trick is trying to enhance the heat-busting power of the vests without making them too heavy or cumbersome.

The most commonly used cooling system is the Interceptor Ventilator Vest, developed by the Natick labs in conjunction with other government agencies and private contractors. The vests were first sent to the Marines last year and about 30,000 are currently in use. Their aerated honeycomb fabric creates a gap between a soldier’s body armour and his body, allowing air to circulate around his torso and back and evaporate perspiration.

Natick’s next generation — called the Body Ventilation System — takes the Interceptor vest a step further.

It involves a battery-powered air blower attached to a soldier’s body to circulate dry air beneath his body armour.

“Regardless of the high-tech cooling systems, soldiers quickly get used to the heat,” Remaley, a 25-year-old medic noted.

“You get acclimatised to it real quick. When it gets hot, you don’t stop what you’re doing.”—AP