EARTHQUAKE: THE LONG ROAD BACK : The Lows of High-Pressure Job : Safety: Firefighters keep 24-hour vigils to monitor water pumped from healthy to quake-damaged mains. It’s a lesson in creativity, boredom and discomfort.

They dreamed of fighting flames and rescuing victims when they became firefighters.

But when a disaster strikes, everyone has a job to do.

Last week’s killer quake prompted Los Angeles Firefighters Terry Onishi and Martin Enriquez to work 24-hour shifts this week from their shiny red engine, monitoring the water pressure of a pair of fire hydrants at a Granada Hills intersection.

The engine, which is parked at the intersection of Chatsworth Street and Petit Avenue, is one of 15 positioned throughout the San Fernando Valley that have been pumping pressurized water from healthy mains into quake-damaged low-pressure mains.

For firefighters like Onishi and Enriquez, monitoring the pressurizing technique, which was last employed in the 1971 Sylmar quake, has been a lesson in creativity, boredom and discomfort. They spent Monday night in a plastic tent erected in front of their engine. It was furnished with a television, a pair of cots, and a stash of food and bottled water.

“We get a lot of strange looks when people just see us sitting there, but it gets to the point where there’s only so much you can do,” Enriquez said.

The diesel-fueled engines have been running virtually nonstop since Wednesday morning, pumping water into a main that runs along Rinaldi Street and down Valley Circle Boulevard.

The 4-foot-wide main was among many that suffered breaks during the quake, leading to difficulties in fighting several quake-triggered fires. In the days following the 6.6-magnitude quake, water outages and low-water-pressure areas were “initially widespread,” throughout the Valley, Battalion Chief Don Dahlstein said.

The pressurizing technique and the magnitude of the operation “is very, very unusual,” but was a necessary response to the devastating effects of last week’s quake, Dahlstein said. At first, 22 engines were pumping water into damaged mains, but the operation has been scaled back as the mains have been repaired.

City firefighters also helped the Department of Water and Power spot breaks in mains by pumping water into the pipes and looking for leaks, the majority of which have been repaired.

Firefighters will continue to pump water into the Rinaldi Street main until the two remaining breaks are fixed, which they estimate will take up to three days.

Nearly 30 water tankers from throughout Southern California have also been assigned to Valley fire stations to provide backup water supplies in case a fire erupts in a low-water-pressure area.

Onishi and Martinez said the toughest part of their assignment has been protecting the fire hose that has been carrying water across Chatsworth Street from being crushed by passing cars. Firefighters built wooden ramps over the hose, which they said ripped out the mufflers on several speeding cars.

“They don’t see the ramp until it’s too late,” Enriquez said.

Another challenge for firefighters has been battling the cold nights. While some firefighters have parked their motor homes near their engines to make the shifts endurable, others have had to survive with makeshift tents.

Onishi said the first two firefighters assigned to monitor the engine at Chatsworth and Petit were left on the corner with a pair of blankets. The two men were abruptly awakened at 3 a.m. when a sprinkler system activated on the lawn where they were sleeping.

“They froze,” he said.

After that episode, firefighters brought cots, and Friday’s shift erected the plastic tarp tent when rumors of rain began to circulate. A television was installed by Sunday, so that firefighters could catch the football playoffs that day.