Can you open doors and windows?

Outside air is especially important when it’s hot

Outside air and good air circulation are always crucial for air quality in the classroom, never more than when it's hot. Many classroom staff seek to open doors and windows in schools lacking a mechanical ventilation system or air conditioning, only to be told by the administration that doors must remain closed and windows can only be opened a few inches. What are the rules?

Natural ventilation

Ventilation diagramNatural ventilation is usually found in older schools, or used in conjunction with other types of ventilation systems. In a natural ventilation system, there is a natural flow of outdoor air coming into the classroom through operable windows, doors, leaks, and other openings in the building envelope. Air is exhausted naturally through windows and other openings such as chimney vents, or through a mechanical exhaust fan on the roof which pulls the air out of the building.

Sometimes the heating system is a unit ventilator (Univent), as in the diagram. These take in outside air, mix it with room air, heat the mix in winter, and blow it into the room. Corridor exhaust fans, and louvers in the door or wall greatly improve circulation.

School districts may interfere with natural classroom ventilation

Schools with natural ventilation can get very hot in hot weather or when the sun pours through windows. But districts often install window stops and order classroom doors to be kept closed. Local associations can work with their UniServ representative, using the information below, to have the district reverse these steps when they are not required by codes, or take other steps to improve indoor air quality in classrooms.

Window stops. Districts may install stops that allow windows to open only 4 to 6 inches, claiming this will prevent a student from falling out. But the stops drastically reduce the amount of outdoor air entering the classroom through the windows. In reality:

  • There are no legal requirements for such stops. The district decided to install the stops and the district can decide to remove them.
  • Children under 6 are most likely to fall out a window. If falls are a true concern, cages or screens can be installed or windows opened from the top.
  • Both the current N.J. Uniform Construction Standard (UCC) and the N.J. Educational Facility Standards require the minimum openable area to be 4 percent of the floor area being ventilated, if there is no mechanical ventilation. For example, in a 20 foot by 20 foot classroom of 400 square feet, there must be 16 square feet of operable window space.
  • The Public Employees Occupational Safety and Health (PEOSH) Indoor Air Quality Standard requires that windows are in operable condition in buildings without mechanical ventilation systems.

Operable windows in schools make sense for many reasons even when a good mechanical ventilation system is present. They allow staff to ameliorate excessive heat, problems with mechanical ventilation, and airing of odors. Windows can provide an emergency exit in case hallways are blocked by smoke or fire. Windows can provide outdoor air in case of nausea, vomiting, asthma attack, urination, defecation, or other health situations.

Open windows are not a solution when occupants with have allergies or asthma caused by grass, pollen or other outdoor allergens. In addition, open windows without screens may admit bees.

Closed doors. Districts often order that classroom doors be kept closed, as a means of avoiding the spread spread of fires. However, the rules that apply are those of the UCC in the year the school was built, back to 1984 (when the UCC first was applied to schools). For older schools, there are no requirements to close the doors, unless the door is fire-rated.

If the school was designed with corridors meant to be fire-protective, the whole corridor is said to be a "fire-rated assembly." This means the walls and doors are fire-resistant, and the doors are meant to be kept closed, usually with an automatic closing device. To find out if you have such a door, look near the hinges, and see if there is a fire-rating label.

Balancing air quality with security

Many staff are concerned about security. The position of the N.J. Department of Community Affairs (NJDCA) is that doors with locks on the inside must be openable without a key, a combination, or other special knowledge or device. This is to ensure quick evacuation in emergencies. Local and district health and safety committees would do well to discuss this balance.

Practical steps for local associations to increase airflow in the classroom

  • Fix ventilation problems. In many older schools, natural cross-ventilation in old buildings has not been maintained, leading to problems like stuck dampers in ductwork and blocked exhaust ducts. Sometimes ductwork has been taken over for computer wiring. You can work with your UniServ representative to have ventilation problems fixed. Rules that apply include:

1. The PEOSH Indoor Air Quality Standard.

2. The UCC at the time of construction. This may include requirements for natural ventilation.

  • Use the Univent with heat turned off. In many schools the heat is supplied by a central boiler, which is turned off in warm weather.
  • Request fans or shades.
  • Be wary of air conditioners. Window air conditioners may make you deliciously cool, but they supply only tiny amounts of outside air. If you have them, you may need to alternate periods of their use with periods of open doors and windows.

Finding the rules that apply to your school

  • N.J. Department of Community Affairs (NJDCA), Division of Plan Review, governs requirements for schools built since 1984: 609-943-5157
  • The PEOSH Indoor Air Quality Standard, Section 12:100 –13.3 (a) 6, requires that public employers ensure that buildings without mechanical ventilation are maintained so that windows, doors, vents, stacks, and other portals designed or used for natural ventilation are in operable condition. Call 609-984-1863, or look at the standard at

PEOSH responds to IAQ complaints first with a letter to administration, and resolution may be lengthy. But local associations can use PEOSH checklists on their own walkthrough, ask to see maintenance records, etc.

  • For questions about fire codes in your school, consult the local fire official. You can find them on the NJDCA web page. If there is no local official, call the DCA Fire Marshal's office at 609-633-6106.

For more information

For NJEA publications, go to “Issues and Actions,” then “Health and Safety,” then:

  • Click onPublications,” then “Organizing for Better Indoor Air Quality,” 2011. Gives detailed background information and a process for the local association to organize around IAQ.
  • Click on “NJEA Reporter Articles,” then “this index” and look for articles on IAQ, including “Ventilation Systems Affect Air Quality,” March 2012.

>> Download this article in PDF PDF