FIMMA product is generated by an automated algorithm and placed on the web page as soon as available. It has not been quality controlled. For a quality controlled product, users are referred to the Hazard Mapping System (HMS) product created by SAB satellite analysts:
http://www.ospo.noaa.gov/Products/land/hms.html

Users should note: 
Fire pixels represent the approximate location of a fire and do not represent the actual fire size. The AVHRR instantaneous field of view at nadir is 1x1 km, but the fire phenomena may be much smaller than that. The algorithm is only accurate over forested regions, and it uses the Univ. of Maryland 1km Global Land Cover Data Set for landcover masking. Only fire pixels occurring  within landcover types with some tree cover are kept as possible fires. The algorithm may miss real fires over urban areas, as well as many agricultural burns. 

If no fires are detected for a given pass, a file is not placed on the server.

The orbital data are available near-realtime, typically 3-6 hours after satellite overpass.