The city emergency sirens at Hanauma Bay and Waialae Beach Park will be tested through the morning today.

Residents and businesses in the surrounding communities may hear several 20-second siren soundings during the testing period that last through noon.

On Friday, fewer than 10 of the state’s 181 sirens failed during the tsunami alert, the City Departments of Emergency Management said. A full assessment is still being conducted.

John Cummings, city emergency management spokesman, said the siren at Hanauma Bay was one of the 10 which didn’t work on Friday because it was off line  waiting for parts so it could be fixed. The one at Waialae Beach Park “had been tagged” for routine maintenance and no one complained, “so we assumed it worked,” Cummings added.

This morning’s tests are being conducted to ensure that these sirens are operating at full power and providing optimal range, the city said.

The range of the siren varies from 2,800 to 6,500 feet, the city said.

The sirens, each costing $86,000, are installed by state Civil Defense and maintained by the city.

They are operated by the city’s Department of Emergency Management or the Honolulu Police Department.

Monthly tests of the sirens generally last 45 seconds and are conducted on the first working day of each month.

During an actual emergency, like Friday’s tsunami, the emeregncy sirens sound a steady tone for 3 minutes, a city spokesman said.

The sirens at Campbell Industrial Park incorporate a special warbling tone for hazard materials emergencies.