JACKSONVILLE, Fla. -- Fire investigators released on Wednesday parts of their report in the investigation of why the pet-filled facility at the Jacksonville Humane Society's Southside headquarters burned and why the building burned as quickly as they did.

The building caught fire early Saturday morning, killing several cats and dogs. Inspectors have since condemned one of the burned buildings at the facility.

Although animals live at the shelter, the facility is listed as a warehouse, which do not need the extra fire protection that office buildings and stores require.

"What that means is in practical terms is this -- life-safety codes, like the maintenance of a sprinkler system, smoke detectors and so on are simply not applicable here. They don't have to have them," said Tom Francis of Jacksonville Fire and Rescue.

Channel 4 also received copies of the Humane Society's inspection reports prior to the fire, and the fire department said the Humane Society was up to code.

Investigators said they still believe the fire started in or near the laundry room. There was no one in the building when the fire broke out, and the fire department said it has ruled out arson.

The Humane Society is expected to rebuild, and is still considering joining forces with the city.

The Humane Society said some big safety changes can be expected with the next facility.

"You learn from your past. The bottom line here is we had devastating fire. As we plan our new site and new facility, we are going to look at all of the safety equipment available to us," said Humane Society Executive Director Leona Sheddan.

Channel 4 said some groups have already donated safety equipment and will install it free of charge.