CHAPTER 4 VENTILATION

SECTION 401 GENERAL

401.1 Scope. This chapter shall govern the ventilation of spaces within a building intended to be occupied. This chap­ter does not govern the requirements for smoke control sys­tems.

401.2 Ventilation required. Every occupied space shall be ventilated by natural means in accordance with Section 402 or by mechanical means in accordance with Section 403.

401.3 When required. Ventilation shall be provided during the periods that the room or space is occupied.

401.4 Vestibule ventilation. Vestibule ventilation for smoke-proof enclosures shall be in accordance with the Florida Building Code, Building.

401.5 Opening location. Outside air exhaust and intake openings shall be located a minimum of 10 feet (3048 mm) from lot lines or buildings on the same lot. Where openings front on a street or public way, the distance shall be measured to the centerline of the street or public way.

Exception: Use Group R-3.

401.5.1 Intake openings. Mechanical and gravity outside air intake openings shall be located a minimum of 10 feet (3048 mm) from any hazardous or noxious contaminant, such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks, except as otherwise spec­ified in this code. Fresh air intakes shall not be located closer than 10 ft (3048 mm) from any chimney or vent outlet, or sanitary sewer vent outlet.

401.5.2 Exhaust openings. Outside exhaust openings shall be located so as not to create a nuisance. Exhaust air shall not be directed onto walkways.

401.6 Outdoor opening protection. Air exhaust and intake openings that terminate outdoors shall be protected with cor­rosion-resistant screens, louvers or grilles. Openings in lou­vers, grilles and screens shall be sized in accordance with Table 401.6. Openings shall be protected against local weath­er conditions. Outdoor air exhaust and intake openings locat­ed in exterior walls shall meet the provisions for exterior wall opening protectives in accordance with the Florida Building Code, Building.

TABLE 401.6 OPENING SIZES IN LOUVERS, GRILLES AND SCREENS

PROTECTING OUTDOOR EXHAUST AND AIR INTAKE OPENINGS

For SI: 1 inch = 25.4 mm.

401.7 Contaminant sources. Stationary local sources pro­ducing air-borne particulates, heat, odors, fumes, spray, vapors, smoke or gases in such quantities as to be irritating or injurious to health shall be provided with an exhaust system in accordance with Chapter 5 or a means of collection and removal of the contaminants. Such exhaust shall discharge directly to an approved location at the exterior of the building.

SECTION 402 NATURAL VENTILATION

402.1 General. Natural ventilation of an occupied space shall be through windows, doors, louvers or other openings to the outdoors.

402.2 Ventilation area required. The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated.

402.2.1 Adjoining spaces. Where rooms and spaces with­out openings to the outdoors are ventilated through an adjoining room, the opening to the adjoining rooms shall be unobstructed and shall have an area not less than 8 per­cent of the floor area of the interior room or space, but not less than 25 square feet (2.3 m2). The minimum openable area to the outdoors shall be based on the total floor area being ventilated.

402.2.2 Openings below grade. Where openings below grade provide required natural ventilation, the outside hor­izontal clear space measured perpendicular to the opening shall be one and one-half times the depth of the opening. The depth of the opening shall be measured from the aver­age adjoining ground level to the bottom of the opening.

402.3 Contaminants exhausted. Naturally ventilated spaces having contaminant sources as covered in Section 401.7 shall be provided with an exhaust system in accordance with Chapter 5 or an approved means of collection and removal of the contaminants.

FLORIDA BUILDING CODE — MECHANICAL 4.1

OUTDOOR OPENING

Exhaust openings

Intake openings in residential occupancies

Intake openings in other than residential occupancies

MINIMUM AND MAXIMUM OPENING SIZES IN LOUVERS, GRILLES AND SCREENS MEASURED IN

ANY DIRECTION

Not < 1/4 inch and not > 1/2 inch

Not < 1/4 inch and not > 1 / 2 inch

> 1/4 inch and not > 1 inch

OCCUPANCY CLASSIFICATION Correctional facilities

Cells Dining halls Guard station

Dry cleaners, laundries Coin-operated dry cleaner Coin-operated laundries Commercial dry cleaner Commercial laundry Storage, pick up

Education Auditoriums Classroom Corridors Laboratories Libraries Locker rooms Music rooms Smoking loungesb

Training shops

Food and beverage service Bars, cocktail lounges Cafeteria, fast food Dining room Kitchens (cooking)f

Hospitals, nursing and convalescent homes Autopsy roomsb

Medical procedure rooms Operating rooms Patient rooms Physical therapy Recovery and ICU

ESTIMATED MAXIMUM

OCCUPANT LOAD, PERSONS PER 1,000 SQUARE

FEET'

20 100 40

20 20 30 10 30

150 50

— 30 20

— 50 70 30

100 100 70 20

— 20 20 10 20 20

OUTDOOR AIR [cubic feet per

minute (cfm) per person] UNLESS

NOTED*

20 15 15

15 15 30 25 35

15 15

0.10cfm/ft2

20 15

0.50 cfm/ft2

15 60 20

30 20 20 15

0.50 cfm/.ft2

15 30 25 15 15

402.3.1 - TABLE 403.3

402.3.1 Bathrooms. Rooms containing bathtubs, show­ers, spas and similar bathing fixtures shall be mechanical­ly ventilated in accordance with Section 403.

402.4 Openings on yards or courts. Where natural ventilation is to be provided by openings onto yards or courts, such yards or courts shall comply with the requirements of the Florida Building Code, Building.

SECTION 403 MECHANICAL VENTILATION

403.1 Ventilation system. Mechanical ventilation shall be provided by a method of supply air and return or exhaust air. The amount of supply air shall be approximately equal to the amount of return and exhaust air. The system shall not be prohibited from producing a negative or positive pressure. The system to convey the ventilation air shall be designed and installed in accordance with Chapter 6.

Ventilation supply systems shall be designed to deliver the required rate of supply air to the occupied zone within an occu­pied space. The occupied zone shall have boundaries measured at 3 inches (76 mm) and 72 inches (1829 mm) above the floor and 24 inches (610 mm) from the enclosing walls.

403.2 Outdoor air required. The minimum ventilation rate of required outdoor air shall be determined in accordance with Section 403.3.

Exception: Where the registered design professional demonstrates that an engineered ventilation system design will prevent the maximum concentration of contaminants from exceeding that obtainable by the rate of outdoor air ventilation determined in accordance with Section 403.3, the minimum required rate of outdoor air shall be reduced in accordance with such engineered system design.

403.2.1 Recirculation of air. The air required by Section 403.3 shall not be recirculated. Air in excess of that required by Section 403.3 shall not be prohibited from being recirculated as a component of supply air to build­ing spaces, except that:

1. Ventilation air shall not be recirculated from one dwelling to another or to dissimilar occupancies.

2. Supply air to a swimming pool and associated deck areas shall not be recirculated unless such air is dehumidified to maintain the relative humidity of the area at 60 percent or less. Air from this area shall not be recirculated to other spaces.

403.2.2 Transfer air. Except where recirculation from such spaces is prohibited by Table 403.3, air transferred from occupied spaces is not prohibited from serving as makeup air for required exhaust systems in such spaces as kitchens, baths, toilet rooms, elevators and smoking lounges. The amount of transfer air and exhaust air shall be sufficient to provide the flow rates as specified in Sections 403.3 and 403.3.1.

4.2 FLORIDA BUILDING CODE — MECHANICAL

(continued)

403.3 Ventilation rate. Ventilation systems shall be designed to have the capacity to supply the minimum outdoor air flow rate determined in accordance with Table 403.3 based on the occupancy of the space and the occupant load or other parameter as stated therein. The occupant load utilized for design of the ventilation system shall not be less than the number determined from the estimated maximum occupant load rate indicated in Table 403.3. Where peak occupancies of less than three hours duration occur, the outside air flow rate may be determined on the basis of average occupancy for the space for the duration of the system, provided the average occupancy used is not less than one-half the maxi­mum. Ventilation rates for occupancies not represented in Table 403.3 shall be determined by an approved engineering analysis. The ventilation system shall be designed to supply the required rate of ventilation air continuously during the period the space is occupied, except as otherwise stated in other provisions of the code.

Exception: The occupant load is not required to be deter­mined, based on the estimated maximum occupant load rate indicated in Table 403.3 where approved statistical data document the accuracy of an alternate anticipated occupant density.

TABLE 403.3 REQUIRED OUTDOOR VENTILATION AIR

TABLE 403.3 (continued) REQUIRED OUTDOOR VENTILATION AIR

For SI: 1 cubic foot per minute = 0.0004719 m3/s, 1 cubic foot per minute per square foot = 0.00508 m3

°C = [(°F)-32]/1.8. ' Based upon net occupied heated or conditioned space. b Mechanical exhaust required and recirculation is prohibited. c Spaces unheated or maintained below 50°F are not covered by these requirements

unless the occupancy is continuous. d Public parking garages shall be ventilated in accordance with Section 403.4 where

the ventilation system is operated by an automatic carbon monoxide detection device.

e Where the ventilation rate is expressed in cfm/ft2' such rate is based upon cubic feet

per minute per square foot of the floor area being ventilated. f The sum of the outdoor and transfer air from adjacent spaces shall be sufficient to

provide an exhaust rate of not less than 1.5 cfm/ft2. g Transfer air permitted in accordance with Section 403.2.2.

FLORIDA BUILDING CODE — MECHANICAL 4.3

(continued)

TABLE 403.3 (continued) REQUIRED OUTDOOR VENTILATION AIR

TABLE 403.3

OCCUPANCY CLASSIFICATION

Hotels, motels, resorts and dormitories

Assembly rooms Bathroomsb

Bedrooms Conference rooms Dormitory sleeping areas Gambling casinos Living rooms Lobbies

Offices Conference rooms Office spaces Reception areas Telecommunication

centers and data entry

Private dwelling single and multiple Living areasc

Kitchens

Toilet rooms and bathrooms

Garages, separate for each dwelling

Garages, common for multiple unitsb

Public spaces Corridors and utilities

Elevatorsg

Locker and dressing roomsb

Toilet roomsb,g

Smoking loungesb

Retail stores, sales floors and showroom floors

Basement and street Dressing rooms Malls and arcades Shipping and receiving Smoking loungesb

Storage rooms Upper floors Warehouses

ESTIMATED MAXIMUM

OCCUPANT LOAD, PERSONS PER 1,000 SQUARE

FEET*

120

— — 50 20

120

30

50 7

60

60

Based upon number of bedrooms

First bedroom: 2; each additional

bedroom: 1

—

—

—

— — —

70

— — — — 70

— — —

OUTDOOR AIR [cubic feet per

minute (cfm) per person] UNLESS

NOTED*

15 35 cfm per room 30 cfm per room

20 15 30

30 cfm per room 15

20 20 15

20

0.35 air changes per houra or 15 cfm per person.

whichever is greater

100 cfm intermittent or

25 cfm continuous Mechanical

exhaust capacity of 50 cfm

intermittent or 20 cfm

continuous 100 cfm per car

1.5 cfm/ft2

0.05 cfm/ft2

1.00 cfm/ft2

0.5 cfm/ft2

50 cfm per

water closet or urinal

60

0.30 cfm/ft2

0.20 cfm/ft2

0.20 cfm/ft2

0.15 cfm/ft2

60

0.15 cfm/ft2

0.20 cfm/ft2

0.05 cfm/ft2

OCCUPANCY CLASSIFICATION

Specialty shops Automotive service

stations Barber Beauty Clothiers, furniture Florists Hardware, drugs, fabrics

Pet shops Reducing salons Supermarkets

Theaters Auditoriums Lobbies Stages, studios Ticket booth

Transportation Platforms Vehicles Waiting rooms

Workrooms Bank vaults Darkrooms Duplicating, printing Meat processingc

Pharmacy Photo studios

Sports and amusement Ballrooms and discos Bowling alleys (seating areas)

Game rooms Ice arenas Playing floors (gymnasiums)

Spectator areas Swimming pools (pool and deck area)

Storage Repair garages, public garages (enclosed)d

Warehouses

ESTIMATED MAXIMUM

OCCUPANT LOAD, PERSONS PER 1,000 SQUARE

FEET*

— 25 25

— 8 8

— 20

8

150 150 70 60

100 150 100

5

— — 10 20 10

100

70 70

— 30

150

—

— —

OUTDOOR AIR [cubic feet per

minute (cfm) per person] UNLESS

NOTED*

1.5 cfm/ft2

15 25

0.30 cfm/ft2

15 15

1.00 cfm/ft2

15 15

15 20 15 20

15 15 15

15 0.50 cfm/ft2

0.50 cfm/ft2

25

25 25

0.50 cfm/ft2

20

15

0.50 cfm/ft2

1.5 cfm/ft2

0.05 cfm/ft2

403.3.1 System operation. The minimum flow rate of outdoor air that the ventilation system must be capable of supplying during its operation shall be permitted to be based on the rate per person indicated in Table 403.3 and the actual number of occupants present.

403.3.2 Common ventilation system. Where spaces hav­ing different ventilation rate requirements are served by a common ventilation system, the ratio of outdoor air to total supply air for the system shall be determined based on the space having the largest outdoor air requirement or shall be determined in accordance with the following formula:

where:

Y = Vot /Vst = Corrected fraction of outdoor air in system supply.

X = Von /Vst = Uncorrected fraction of outdoor air in system supply.

Z = Voc /Vsc - Fraction of outdoor air in critical space. The critical space is that space with the greatest required fraction of out­door air in the supply to this space.

Vot = Corrected total outdoor airflow rate.

Vst = Total supply flow rate, i.e., the sum of all supply for all branches of the system.

Von = Sum of outdoor airflow rates for all branches on system.

Voc= Outdoor airflow rate required in critical spaces.

Vsc= Supply flow rate in critical space.

403.3.3 Variable air volume system control. Variable air volume air distribution systems, other than those designed to supply only 100-percent outdoor air, shall be provided with controls to regulate the flow of outdoor air. Such con­trol system shall be designed to maintain the flow of out­door air at a rate of not less than that required by Section 403 over the entire range of supply air operating rates.

403.4 Public garages. Mechanical ventilation systems for public garages are not required to operate continuously where the system is arranged to operate automatically upon detection of a concentration of carbon monoxide of 25 parts per million (ppm) by approved automatic detection devices.

403.4.1 Minimum ventilation. Automatic operation of the system shall not reduce the ventilation rate below 5 cfm (0.0024 m3/s) per person and the system shall be capable of producing a ventilation rate of 1.5 cfm per square foot (0.0076 m3/s m2) of floor area.

403.5 ASHRAE 62 Alternative. In lieu of compliance with Section 403.1 through 403.4, mechanical ventilation may be implemented in compliance with ASHRAE 62 including approved addenda.

403.6 Smoke control. Smoke control systems for selected occupancies shall comply with Sections 403.6.1 through 403.6.7.

403.6.1 Stages. Emergency ventilation shall be provided for all stage areas greater than 1,000 sq ft (92.9m 2) or with a stage height of greater than 50 ft (15.2 m) to provide a means of removing smoke and combustion gases directly to the outside in the event of a fire. Ventilation shall be by one or a combination of the following methods:

1. Smoke control: A means shall be provided to main­tain the smoke level not less than 6 ft (1829 mm) above the highest level of assembly seating or above the top of the proscenium opening where a prosce­nium wall and opening protection is provided. The system shall be activated independently by each of the following: (1) Activation of the sprinkler system in the stage area and (2) by a manually operated switch at an approved location. The emergency ven­tilation system shall be connected to both normal and standby power. Fan power wiring and ducts shall be located and properly protected to assure a minimum 20 minutes of operation in the event of activation.

2. Roof vents: Two or more vents shall be located near the center of and above the highest part of the stage area. They shall be raised above the roof and pro­vide a net free vent area equal to 5% of the stage area. Vents shall be constructed to open automati­cally by approved heat-activated devices. Supplemental means shall be provided for manual operation of the ventilator from the stage floor. Vents shall be labeled by an approved agency.

403.6.2 Special hazardous occupancies. Areas within hazardous occupancies storing liquid and solid oxidizers, organic peroxides, unstable (reactive) materials or water reactive materials shall be provided with means to vent smoke and heat in a fire or other emergency. Smoke and heat venting shall be designed in accordance with the Florida Fire Prevention Code.

4.4 FLORIDA BUILDING CODE — MECHANICAL

403.3.1 - 403.6.2

403.6.3 Institutional restrained occupancies. Windowless Group I restrained buildings shall be provid­ed with vent openings, smoke shafts, or an engineered smoke control system approved by the building official to provide ventilation, mechanical or natural, for each win­dowless smoke compartment.

403.6.4 Group B and Group R high rise buildings. Natural or mechanical ventilation for the removal of products of com­bustion shall be provided in every story of a Group R or Group B high rise building and shall consist of one of the fol­lowing:

1. Panels or windows in the exterior walls which can be opened remotely from an approved location other than the fire floor. Such venting facilities shall be provided at the rate of 20 sq ft per 50 linear ft (1.86 m2 per 15 m) of exterior wall in each story and shall be distributed around the perimeter at not more than 50 ft (15 m) intervals. Such windows or panels and their controls shall be clearly identified.

2. In a building which is equipped with an approved complete automatic sprinkler system, windows or panels manually openable from the fire floor or pan­els of approved, fixed, fully tempered glass may be substituted for the remotely operated openable pan­els or windows. Such manually openable windows or fixed tempered panels shall be clearly identified and shall be of the size and spacing required in 403.6.4(1).

3. In a building which is equipped with an approved complete automatic sprinkler system, properly designed mechanical air handling equipment may be substituted for the natural ventilation described in 403.6.4(1) and 403.6.4(2), provided that the air handling equipment is connected to the standby power and light system. Under fire conditions, the return and exhaust air shall be moved directly to the outside without recirculation to other sections of the building. The air handling system shall have the capability of providing a minimum of one exhaust air change every 10 minutes for any area which might be involved.

4. Any other design which will produce equivalent results may be considered by the building official.

403.6.5 Covered mall buildings. 403.6.5.1 Smoke detectors shall be provided within an air conditioning system in accordance with Section 606 of this code. Actuation of either a smoke detector or the sprinkler system shall cause the air supply to the air conditioning zone in which the fire occurs to shut down.

403.6.5.2 The mall shall have smoke removal capabil­ity installed in or near the roof. Such facility may be either natural or mechanical.

403.6.5.3 Before the systems are accepted by the build­ing official, they shall be tested in his presence to con­firm that they are operating in compliance with the requirements of this section.

403.6.6 Atriums. A smoke control system shall be designed to control the migration of products of combus­tion in the atrium space. Upon detection of a fire, the sys­tem shall shut down the air supply to the fire floor and the return air from all nonfire floors. Any other approved design which will achieve the same level of smoke control as described in this section may be used in lieu of these requirements.

403.6.6.1 In atriums 55ft (16.8 m) or less in height with a volume of 600,000 cu ft (16992 m3) or less, a smoke exhaust system shall be located at the ceiling of the atrium. Such systems shall exhaust 40,000 cfm (18.93/s). When the volume of the atrium exceeds 600,000 cu ft (16992 m3) the exhaust system shall be sized to provide a minimum of four air changes per hour.

403.6.6.2 Supply air inlets may be provided at the low­est level of the atrium. These inlets shall be sized to provide 75% of the exhaust.

403.6.6.3 For purposes of this section, the volume of the atrium shall include all spaces not separated from the atrium as provided in 414.5 of the Florida Building Code, Building.

403.6.6.4 When the height of the atrium exceeds 55ft (16.8 m), an exhaust system shall be provided as required in 403.6.6.1; however, supply air shall be introduced mechanically from the floor of the atrium and shall be directed vertically at the exhaust outlet above. The capaci­ty of the supply shall be 75% of the exhaust.

403.6.6.5 Manual controls shall be provided for the atrium smoke control system. When the smoke control system in other than the atrium is provided by mechan­ical ventilation in accordance with 403.6.6.6, manual controls shall also be provided as described above for the atrium system. The manual controls shall be pro­vided in a location approved by the building official.

403.6.6.6 In any building containing an atrium, occu­pied space that does not open directly to the atrium shall be designed to provide natural or mechanical ven­tilation in accordance with 403.6.4.

FLORIDA BUILDING CODE — MECHANICAL 4.5

403.6.3 - 403.6.6.6

403.6.7 - 404.1

403.6.7 Underground buildings. Where compartmenta-tion is required, each compartment shall have an inde­pendent, automatically activated smoke exhaust system capable of manual operation. The system shall have an air supply and smoke exhaust capability which will provide a minimum of six air changes per hour.

403.6.7.1 The smoke exhaust system shall be operated in the compartment of origin by the following inde­pendently of each other:

1. Two cross-zoned smoke detectors within a single protected area or a single smoke detector moni­tored by an alarm verification zone or an approved equivalent method.

2. The automatic fire sprinkler system. 3. Manual controls that are readily accessible to the

fire department.

403.6.7.2 Activation of the smoke exhaust system shall activate an audible alarm at a constantly attended loca­tion.

SECTION 404 VENTILATION OF UNINHABITED SPACES

404.1 General. Uninhabited spaces, such as crawl spaces and attics, shall be provided with natural ventilation openings as required by the Florida Building Code, Building or shall be provided with a mechanical exhaust and supply air system. The mechanical exhaust rate shall be not less than 0.02 cfm per square foot (0.00001 m3/s m2) of horizontal area and shall be automatically controlled to operate when the relative humidity in the space served exceeds 60 percent.

4.6 FLORIDA BUILDING CODE —MECHANICAL