The D.C. City Council is scheduled to vote Tuesday on a bill that would require smoke detectors in all existing and new homes, duplexes and apartments, hotels, motels, hospitals, nursing homes, jails, prisons and resident-custodial care facilities in the city.

The D.C. Fire Department, one of the original backers of the legislation, estimates that installation of smoke detectors would reduce by half the number of fatalities that result from fires. In 1977, there were 43 persons who died in fires here, and the fire department estimates that 21 of those might have been saved if smoke detectors had given accupants an earlier warning.

The National Fire Protection Association has called smoke detectors the most effective way to reduce residential fire deaths, which usually occur at night. The device, which sounds an alarm when smoke is detected, gives sleeping residents a few extra moments' warning so they can get out.

Owners of existing residences would have three years from the time the legislation took effect to install smoke detectors. The District would have two years to provide smoke detectors in facilities it owns and operates.

The smoke detector bill also requires installation of smoke detectors in newly-constructed homes and facilities as well as those which are substantially rehabilitated beginning Oct. 1, 1978.

At least one smoke detector would have to be installed in each "sleeping area," according to the legislation. In many homes, the detectors would be placed in the hallway near the bedrooms.

Owners of hotels and motels would have to install at least one smoke detector to protect each guest room and guest suite. Owners of hospitals, nursing homes, jails, prisons and residential-custodial care facilities could install smoke detectors in the corridors adjacent to rooms used for sleeping or in the rooms themselves.

In new residences, the smoke detectors would have to be wired directly to the power supply of the building. In existing residences, owners could install direct-wire smoke detectors or they could connect the smoke detector to an electrical plug-in outlet. Only in single-family homes could people also use a monitored battery powered smoke detector.The monitored battery powered detector emits a signal when run-down batteries need replacement.

The owners of homes, apartments and other residences would be responsible for maintaining the smoke detectors in operating condition and making periodic inspections.

If the council approves the bill Tuesday, it will have to be approved once more by the council and signed by the mayor. The bill must be reviewed by Congress, which usually takes about two months, before it could become law.

According to the fire department, 25 states and many cities and counties currently require installation of smoke detectors in new residential construction. In the Washington area, Montgomery and Prince George's counties have already enacted smoke detector legislation.

For homeowners or apartment owners, the bill's passage smoke detectors which range in price from about $25 to $45, depending on the model, according to Fire Marshall John P. Breen of the D.C. Fire Department. Sales of smoke detectors reached 8 million in 1976, he said, and "it is safe to assume that the cost per unti will decrease as production increases."

The D.C. Fire Department endorses smoke detectors which have been approved by either Underwriter Laboratories or Factory Mutual Laboratory.

In its study of the proposed legislation, the council's Judiciary Committee said that if the bill were enacted its cost to the city would be "minimal." It "will require the District to outlay a maximum of $426,250," the report said, but the city "should recover $400,000" from the U.S. Department of Housing and Urban Development, primarily in Community Development block grand funds. The committee said that the "long term fiscal impact" of the bill "is under $26,250."

The legislation would be enforced by integrating the smoke detector requirements into the fire prevention code, housing regulations, the city's electrical code, building code and health care facilities regulation, according to the Judiciary Committee. The city would enforce the smoke detector legislation in the same manner it currently enforces those regulations.

Housing inspectors would routinely check for smoke detectors in all dwellings. The District of Columbia could issue a notice of housing violation to any dwelling owner who fails to install smoke detectors. The city could fine or imprison a dwelling owner who does not comply.

If an owner refused to comply, the District could actually install smoke detectors and add the costs to the owner's tax bill.

The smoke detector bill that will go before the Council Tuesday was originally introduced by Council Member Willie J. Hardy last May. A similar bill was introduced by Council Chairman Sterling Tucker at the request for Mayor Walter E. Washington.

A public hearing on both bills was held by the Committee on the Judiciary last July. At that time, the legislation applied only to dwelling units in which a family or individual lived, including those owned or operated by the District.

Witnesses at the public hearing suggested that the bill should be expanded to include hotels, motels, hospitals, nursing homes, jails, prisons and residential-custodial care facilities, to give people who live in those places the same protection.

The Judiciary Committee voted Jan. 31 to approve the amended bill. The vote was three in favor - council members David A. Clarke, chairman of the committee, Arrington Dixon and Wilhelmina Jackson Rolark; none opposed, and two absent - Marion S. Barry and Willie J. Hardy.