AQMW_FireSuppressionNarrative_IL_R1.pdf

Automatic Fire Sprinkler System for the Quartermaster Warehouse Building at Alcatraz Island

Automatic Fire Sprinkler Requirements

The Quartermaster Warehouse Building at Alcatraz is proposed to be renovated.

The uses will remain approximately the same and will include storage, maintenance shop area, vehicle parking for the historic fire truck, and vehicle maintenance area.

The preliminary code analysis, based on the applicable 2012 International Building, Fire, Existing Building Codes and the 2013 California Historical Building Code concludes that an automatic fire sprinkler system is necessary based on the following code sections:

California Historical Building Code Chapter 8-1

CHBC 8-102.1.6 Additional work. Qualified historical buildings or properties shall not be subject to additional work required by the regular code, regulation or ordinance beyond that required to complete the work undertaken. Certain exceptions for accessibility and for distinct hazards exist by mandate and may require specific action, within the parameters of the CHBC.

Based on this code section, several distinct hazards are present that would imply that an automatic fire sprinkler system is necessary for the building:

1. Lack of on island fire station at Alcatraz. The lack of a local responding, professional fire department and the resulting delays associated with fire fighting establishes a distinct hazard for the building. In particular, the building houses batteries as part of the electrical supply for the island operations. An uncontrolled fire, with associated fire department delays could impact the battery room and result in an interruption in power for the island. A sprinkler system can protect the battery room from building collapse due to fire or from fire spreading from the storage areas affecting the battery room.

2. The battery room. The battery room is a distinct hazard. If a fire were to start in any portion of the building, it can grow to a significant size before the fire department arrives. In turn, if fire were to spread to the battery room, the chemicals associated with the batteries may create an environmental concern.

2012 International Existing Building Code

703.2.1 Existing Vertical Openings. All existing interior vertical openings connecting two or more floors shall be enclosed with approved assemblies having a fire-resistance rating of not less than 1 hour with approved opening protectives.*

Exceptions:

7. In Group F occupancies, the enclosure shall not be required in the following locations:

7.1 Vertical openings not exceeding three stories

13. Group S occupancies where connecting not more than two floor levels or where connecting not more than three floor levels and the structure is equipped throughout with an approved automatic sprinkler system.

Based on the preceding code section, the proposed unenclosed elevator/lift in the QM

Warehouse creates a need for a fire sprinkler system.

2012 International Building Code, Chapter 9 – Fire Protection Systems

IBC 903.2.9 Group S-1. An automatic sprinkler system shall be provided throughout all buildings containing a Group S-1 occupancy where one of the following conditions exists:

1. A Group S-1 fire area is located more than three stories above grade plane.

Based on the preceding code section, the introduction of storage at the 2 nd floor (which is three stories above grade), could be interpreted to necessitate an automatic fire sprinkler system.

In summary, there is substantial code basis for providing an automatic fire sprinkler system for the Quartermaster Warehouse Project. Moreover, the lack of fire department or professional fire fighting staffing on the island, and the associated potential delays upwards of 20 to 30 minutes for fire fighting operations is a major concern, particularly for a storage and maintenance building. Without early intervention and without a fire sprinkler system, it can be expected that a fire in the Quartermaster Warehouse could overwhelm the responding fire department, resulting in complete loss of the contents and possibility of building collapse. With collapse, the battery room may be lost which would also create significant business and tourist interruption. These additional factors support the need for a wet pipe automatic fire sprinkler system for the structure.

Automatic Fire Sprinkler System: Basis of Design

The proposed wet pipe automatic fire sprinkler system design (system) has been developed in collaboration with the presiding Fire Marshal in accordance with the intent of the codes. The system is designed to protect Ordinary Hazard Group 2 (OH2) occupancies – and is therefore appropriate for office spaces, vehicle storage, rack storage up to 8 feet, and maintenance shops. OH2 systems are typically designed to include sprinklers spaced every 130 square feet. It is expected that the system, designed in accordance with the code, will provide appropriate and effective suppression of a fire with the potential for extinguishment. Automatically activated suppression keeps the fire from growing and spreading and provides time necessary for the fire department to respond to perform final extinguishment if necessary.

The system is designed to draw water from the two existing on-island water tanks. The water tanks, located at higher elevations, have a total volumetric capacity of 21,800 gallons. The code requires that the sprinkler system be fed for a minimum of 60 minutes.

Consequently, flow calculations estimate that a minimum of 18,000 gallons are necessary. Therefore, the two tanks are deemed to provide adequate water supply.

The tanks will feed new underground piping that will be routed in an existing utility trench towards the QM Warehouse building. Some additional trenching will be necessary to reach the building; however, it is reported that such trenching will be provided as part of the current project for other utilities.

The new underground piping will feed a new fire pump proposed at the lowest level of the project inside a new fire pump room. The fire pump is necessary to feed the system such that adequate pressure and flow is provided at the furthest hydraulically demanding area in the system, most likely at the ceiling of Level 2. Suggested locations and arrangement of fire pump room piping including a system riser is shown on the drawings, however these may be modified upon approval for coordination during bid and construction. The fire pump will be provided with a fire pump controller system and a test header for testing and maintenance.

The Fire Marshal indicated that no fire department connection for pumper truck connection is necessary because pumper trucks are not available or expected during fire fighting operations. The lack of a fire department connection is not expected to affect basic sprinkler system effectiveness.

In collaboration with the Fire Marshal the design team has decided to include a hose valve connection for responding fire fighters on the discharge side of the fire pump. This is useful for first responders who may be carrying 1-1/2 hose lines for the purposes of final extinguishment. Because it is not required for the project, a standpipe serving outlets on other floors will not be provided.

Sprinklers will not be provided for the battery room; the code permits certain rooms to omit sprinklers if separated from all other areas by 2-hour fire resistive construction.

Such omissions are restricted to certain types of rooms and must be approved by the authority having jurisdiction. Electrical rooms, such as the battery room, are one of the types of rooms that may omit sprinklers. Therefore, the battery room will not be directly protected by the system; however the system, provided throughout all other areas of the building, will indirectly protect the room by suppressing any fire elsewhere from impacting the building’s structural integrity or spreading to the battery room.