A decision must be made as to what type backup line will assist rescuing/protecting the attacking firefighters.
Does it need to be a foam line or a regular line, what size?

How will you rescue the firefighters attacking the fire or applying foam on the spill?:

If the firefighters are standing in applied foam which is covering the spilled fuel, area where a fuel fire has been suppressed or HAVE THE POTENTIAL to be in the fuels from tank failure, spreading fuel,
or covered by fuel during an explosion,........they should be protected by a foam back up line.

If the attacking firefighters are applying foam from a distance or not in the immediate fuel area you may consider a regular line or provide a RIT (Rapid Intervention Team) to rescue those personnel.

Backup off of same apparatus

Backup off of separate apparatus

1 Engineer
1 area to manage buckets
Fewer personnel
Eductor must be retrieved from other apparatus.
No backup if engine/pump or water supply fails

2 Engineers
More area to manage buckets
More personnel
Backup works if engine/pump or water supply fails for primary pumper

Note: Personnel, new buckets and other equipment may be shifted to the backup pumper if primary has totally failed.