"Less than five per cent of the classroom was damaged."
He said the cause of the fire had been identified, but could not comment further. Initially it was believed to be suspicious.
Yesterday a police spokeswoman said it was believed the fire had been "deliberately lit", and that Hawke's Bay Police would be working closely with the school.
Mr Peachey said the school had handled the incident "very well" yesterday.
"Once the fire was noticed the school evacuated everybody properly. The teacher used a couple of extinguishers to put the fire out."
The male teacher was taken to Hawke's Bay Hospital by St Johns Ambulance in a moderate condition.
Yesterday a Hawke's Bay District Health Board spokeswoman said the male teacher had been discharged from hospital.
Staff at Richmond School were unavailable to comment.
However the school posted on social media yesterday afternoon about the "small fire", assuring whanau that students and staff were safe.
"We want to reassure you that the incident is being taken care of. School will be open as normal tomorrow."
According to the school website, the school has a roll of 150.