What kind of fire watch services are available for construction sites when there is no active alarm system?

Construction sites are often high-risk areas due to the open use of power tools and temporary structures. If an alarm system is not yet installed or active, constant monitoring is necessary. When searching for Fire Watch Guards, I noticed that such services are often available 24/7. This is important because risks on the site do not disappear at night or on weekends. In my case, everything was organized without any downtime.