Rob Marsh, principal at Cathedral Academy, where the blaze broke out yesterday morning, said they reacted quickly and calmly to contain the fire.
He said: “We are grateful to the staff who reacted quickly in an emergency situation to ensure that procedures were followed and damage was therefore limited.
“Staff actually saw the fire ablaze which must have caused panic but they remained calm and acted quickly and we are thankful to them for that.”
Fire crews from Ossett and Wakefield were called to the school on Thornes Road at around 6am yesterday.
The West Yorkshire Fire and Rescue Service said staff closed a door to prevent the fire spreading to other parts of the building.
A post on its Twitter feed read: “Fortunately no-one was harmed in this fire... Sadly pupils’ artwork was lost.”
Watch Commander of Wakefield Fire Station Simon O’Hara added: “One of the classrooms was totally engulfed in fire. Fortunately, fire protection systems including an alarm and early warning system and fire doors, helped to stop the flames from spreading, as did the quick actions and intervention of fire crews.”
The academy was closed to Year 7 to 10 students yesterday, but remained open for Year 11 pupils, post-16 students and those who had examinations.
It has re-opened fully today.
In a letter to parents Mr Marsh said: “I am aware that the closure caused lots of issues for parents in terms of childcare and in some cases transport and I appreciate your understanding in this matter.
“I can assure you that we took the most sensible decision in the circumstances to ensure the safety of all staff and students.
The circumstances are that we had a small fire in the school. Fortunately this was isolated to one classroom in the school and the only lasting damage is to that room which will need to be fully refurbished in time.
“Additionally, much of the students art work is affected and this will be upsetting for some students.
“Despite this, exam work had already been assessed and so grades will not be adversely affected, nor will anyone who is currently studying art or is due to start an art course soon.”
He added: “We are fortunate that it happened very early in the morning before any students were in the building.”
The cause of the fire is still being investigated.