A fire alarm keeps beeping mainly due to these reasons:

• Low Battery: The most common cause is a low or dying battery. The alarm beeps as a warning to replace the battery soon.
• Dust and Debris: Dust, cobwebs, or insects inside the alarm sensor can block its detection ability, causing false beeping.
• Aging Smoke Detector: Smoke detectors typically last about 10 years; after that age, they may malfunction and beep.
• Interconnected Alarms: If multiple alarms are interconnected, a malfunction or false trigger in one can cause all to beep.
• Electrical Issues: Loose wiring or power supply problems can trigger intermittent beeping.
• Environmental Factors: Heat, humidity, or incorrect placement near kitchens or bathrooms may cause false alarms.

Checking and replacing batteries, cleaning the alarm sensor chamber, ensuring proper placement, and replacing old alarms typically resolve beeping issues.