Final answer:
Existing non-severe hazard labs need fire-resistant walls and self-closing, fire-rated doors. New or upgraded labs might have stricter requirements based on hazard assessment.
Step-by-step explanation:
The question relates to the design standards required for existing laboratories based on their risk level.
While specific codes and standards can vary by jurisdiction, generally speaking, existing labs that are not considered a severe hazard require fire-resistant walls and self-closing, fire-rated doors.
For new labs or upgraded facilities, the requirements may be stricter, potentially including features such as more advanced fire suppression systems or additional safety measures based on an assessment of the hazards present.