Rescue One pulled up to Eliot House last Friday afternoon to find smoke seeping out of a belfry.

Within two minutes, three engines full of water and two ladder trucks packed with prongs and hooks cluttered Winthrop, JFK and Dunster Streets.

Fortunately, it was a false alarm--that night's beef dinner had apparently gotten a bit too hot.

But the fast and large-scale response is telling of Harvard's location in one of the best-protected areas, fire-wise, in the country.

This past summer, with a little bit of fanfare, the Cambridge Fire Department (CFD) was classified as "ISO Class One."

It sounds like just a technical accolade, but the prestigious ranking has real consequences for Cambridge residents.

It means insurance rates for Cambridge businesses and residents will surely decline.

And it means that national experts have declared Cambridge has, on average, the best fire department in Massachusetts.

Fire Factors

Considering Cambridge's cityscape, this is counterintuitive.

Cambridge is one of the oldest cities in America. It's packed with people from block to block.

Housing ranges from precarious, blaze-prone clapboards to cavernous high-rises.

Adding to the potential danger are the dozens of companies producing hazardous waste, and the universities with complex chemical laboratories.

Subways, too, are prone to fire. Underground water systems blow manhole covers 50 feet into the air.

Since insurance rates are based in part on how well cities can respond to potential disasters, and the above factors affect the fire department more than any other city agency, the fire department's quality is a major factor in insurance rates.

To help insurance companies zero in on rates, the New-York-based Insurance Services Office assesses fire departments around the country. That's the ISO of Cambridge's ISO Class One designation.

Getting to Class One

The ISO's ranking procedure is complicated and involves dozens of factors, according to Dave Dasgupta, a company spokesperson.

This ranking procedure is complicated and involves dozens of factors, Dasgupta says. Fifty percent of the grading is based on the fire department itself, 10 percent on the fire department's communication abilities (the time it takes for a dispatcher to send the closest fire company to the emergency), and 40 percent on how the city copes with high water demand in a crisis.

For fire departments, good equipment, personnel and response time are the best indicators of a quick "knock-down," firefighter lingo for quieting a blaze.

Good departments run an aggregate of water-pumping engines--the front line of defense, first to the fire. The engines are backed up by the trucks, whose firefighters rescue trapped people and ventilate fire buildings. For cities with special needs--say, a large chemical-spewing plant near a residential area--apparatus and personnel trained to handle hazards are key.

Equipment needs to be top-notch. Good departments should use a variety of nozzles to disperse water and be able to distinguish between different types of axes for different types of walls. Solid, non-worn hoses deliver the smoothest water.

For a city its size, Cambridge is well-equipped, with eight engines and four trucks.

Staffing, too, is important. Technological advances mean that fewer firefighters are required to operate hose lines and other equipment. Nevertheless, insurance agencies believe that a bigger crew means a better, faster, response.

The other 50 percent of the ISO equation--water availability and communication--is considered a measure of how well the city handles the needs of its growing population.

The maximum score any community can have is 100; Class One communities have a score between 90 and 100, according to Dasgupta.

Top of the Pack

For the Cambridge Fire Department, getting that top score has been a priority for a while, says Gerald Reardon, a CFD Deputy Chief.

A Class Two department for years, "Cambridge has been always looking to upgrade," Reardon says. " Chief [Kevin] Fitzgerald has made it a priority to try to work on what was needed. They did that very well."

In the early spring, a team of ISO inspectors began to search through records at the Cambridge Fire Department. They observed training exercises and actual fireground operations. They talked with firefighters, dispatchers and chiefs.

Then, this July, the good news. Cambridge had made the cut. It had scored above a 90.

In a word, says Reardon, the distinction is "incredible."

For firefighters, "it's obviously a coveted rating."

No other fire department in Massachusetts--not Boston, not Lynn, not Logan Airport, not Seekonk--is Class One.

Many are classes two, three, and four; there are 10 classes overall. A class 10 ranking means an area has little or no fire protection. Many rural areas receive this designation.

Only 33 departments in the country--that's 33 out of 43,000--merit a Class One ranking.

This one little number, say both Dasgupta, an insurance industry spokesperson, and Reardon, a fire department spokesman, can mean a substantial savings for residents.

Although ISO's ratings most directly affect commercial insurance rates, they often affect residential rates as well.

"I can tell you that if [someone] lives in Woburn, a class four, and [someone] lives in the same house in Cambridge, your rates will be lower" in Cambridge, Dasgupta says.