Description:FIELD OF INVENTION

The hazard of any occupancy is defined as the relative danger of the start of fire or smoke. The danger of smoke or gases generated and spread of fire & smoke across the occupancy, explosion or other occurrences potentially endangering the lives and safety of the occupants. The National Building Code (NBC) of India, therefore, requires that all Air Handling Units (AHU’s) or Systems be interfaced with the Main Fire Alarm panels to prevent smoke spread across Smoke and Fire compartments. These may include tripping of AHU’s, closing, or opening Smoke & Fire dampers or starting smoke extract or pressurization fans. Interface to such mechanical equipment is usually via relay control modules which are connected to Local Control Panels (LCP) of the respective mechanical equipment.

OBJECT OF THE INVENTION

A simplified approach to trip Air Handling System or Equipment, in case of a confirmed fire, is developed using a single point of interface between the Fire Alarm System and the Air Handling Equipment.

The present scheme adopted by fire protection designers uses a method to trigger every Fire Damper through control modules located at every damper location. Local Power supply and control units are required at every fire damper location to actuate these in case of fire. An interface scheme is developed to control mechanical equipment (AHU’s and fire dampers) in case of confirmed fire at a single point of interface instead of the conventional multiple point of interfaces.

Hence this invention attempts to overcome the suffering of the prior art.

DESCRIPTION OF THE DRAWINGS

The circuit diagrams for tripping of motorized fire dampers and Air handling units are presented in Fig. 1 and Fig. 2 respectively. The point of interface shall be between Fire alarm control module and Local Control Panel of the AHU / Motorized Fire Dampers which is indicated as “signal from fire alarm control module” in Fig. 1.

DESCRIPTION OF SCHEME AS PER THE INVENTION

The Local Control Panel (or LCP) of the Air Handling System has the incoming lines as indicated in the scheme represented by Fig. 1 & Fig. 2.

Tap offs are made to connect to the motorized fire dampers in the following manner as indicated in Fig. 1:

a. Tap off 1: Provided from the incoming line to connect motorized fire dampers which operates on a 240V AC supply

b. Tap off 2: Taken from TB a & TB b to connect motorized fire dampers which operate on 24V AC and further connected via an AC/DC converter to motorized fire dampers which operates on 24V DC.

The scheme indicates the relays FD1, FD2 and FD3 with two (2) Normally Open (NO) and Normally Closed (NC) potential free contacts and the relay operates at 24 V DC Supply.

The power supply for the fire dampers is routed through One (1) Normally Closed Contact of Relays FD1, FD2 & FD3 and its another Normally Closed Contact are connected to AHU control circuit through series.
The interface to this circuit is done using one (1) control module connected to the fire alarm panel. Once the signal received from fire alarm control module, all three relays get activated and its Normally Closed Contacts Open and thereby trip the respective dampers.

a. FD1/1 will be used to trip dampers which operate on 24V DC supply
b. FD2/1 will be used to trip dampers which operate on 240V AC supply; and
c. FD3/1 will be used to trip dampers which operate on 24V AC supply

The another Normally Closed (NC) contact (FD1/2, FD2/2, FD3/2) of the relay will trip the Air handling Unit (AHU) as indicated in Fig. 1, Fig. 2 and Fig. 3.

Part no. Part names
301 Signal From Fire Alarm Control Module
302 Operates Fire Relay FD1
303 Operates Fire Relay FD2
304 Operates Fire Relay FD3
305 Normally Closed Contact (NC) FD 1/1 Will Trip 24V DC Operated Fire Dampers
306 Normally Closed Contact (NC) FD 1/2 Will Trip AHU
307 Normally Closed Contact (NC) FD 2/1 Will Trip 240V AC Operated Fire Dampers
308 Normally Closed Contact (NC) FD 2/2 Will Trip AHU
309 Normally Closed Contact (NC) FD 3/1 Will Trip 24V AC Operated Fire Dampers
310 Normally Closed Contact (NC) FD 3/2 Will Trip AHU

The Fire dampers can be triggered by tripping the supply at AHU Local Control Panel instead of local tripping at each damper location using the scheme detailed herein.

The invention relates electrical isolation network fire alarm control module adapted for controlling a plurality of fire alarm relays. Each relay having a pair of normally closed contact (NC), one capable of being coupled to a fire damper and second capable of being coupled to AHU and with each rely also having a pair of normally open contact (NO) capable of being coupled to a source of power through the fire alarm control module. The operable power supply voltage of each of the plurality of associated fire dampers is not the same as the other. The AHU has a local control panel (LCP) with incoming lines and it has plurality of TAP off each operating at a specific voltage supply for tripping a fire damper operating at specific voltage supply, and the said arrangement is novel in that each relay through its first NC contact adapted to trip a damper operating at a specific power supply only and each relay through its second NC contact of the relay is also adapted to be tripped by its corresponding AHU, such that fire dampers are triggered by tripping the supply AHU control panel instead of local tripping at each damper.

The following are the benefits of this scheme:

a. All Voltage ranges of dampers and Air handling units can be controlled by the scheme. 24V DC; 24V AC and 240V AC dampers and air handling equipment can be controlled by interfacing one (1) control module with the local control panel.
b. Reduction in number of control modules as interface with each damper is negated.
c. Associated wiring from the main fire alarm control panel to the control module is reduced.
d. A fail-safe system is ensured.

V. DESCRIPTION OF INVENTION

Important terminologies used to present this disclosure is described below:

a. Air handling units: The appropriate ventilation requirements for purifying, airconditioning, or replenishing the interior air in a building or premises are housed in an air handling unit, also known as an AHU, which is made up of elements mounted in big, accessible box-shaped units called modules. They are commonly put on the roofs of buildings or at the floor in which they serve, and the air is circulated through ducts to each of the rooms within the structure of the building.

b. Fire Compartment: Any place within a building or premise that is enclosed on all sides by fire barriers including the ceiling and floor is referred as a fire compartment. Fire compartments are a sort of passive fire protection systems that are designed to limit the spread of fires and smoke in a facility by preventing fires and smoke from spreading beyond the compartment where they started. The floor areas are separated
into different fire compartments to prevent fire and smoke from spreading.

c. Fire and Smoke Damper: This is a component of the air handling system. The principal function of a smoke damper is to limit smoke movement in dynamic air distribution systems by reducing the probability of smoke transfer through ductwork or through wall apertures. Hourly fire ratings are provided on fire dampers. These dampers have actuators which open or close them in case of emergency. These actuators work on either 240 V AC / 24V AC or 24V DC power supply.

d. Fire alarm system: These are installed in buildings to detect fire through smoke / heat, warn occupants and control fire-related emergencies equipment such as Air Handing Systems, Smoke Management Systems, Access control Systems, Pressurization Systems, etc., The fire alarm System can be triggered or activated automatically from smoke detectors, and heat detectors or may also be activated via manual fire alarm activation devices such as manual call points or pull stations.

e. Control module: This device is intended to regulate external appliances such as door closers, fans, and dampers using a potential free contact.

f. Interface: When two or more fire detectors are activated or when a manually operated call point is triggered, the respective mechanical unit or series of units in a
fire compartment or floor are required to be controlled by the Fire Alarm Panel.

Thus, it can be seen that there has been shown and described a novel control system, and it is to be understood, however, various changes, modifications, substitutes in the form and the details of described fire alarm control system can be made by those skilled in the art without departing from the scope of the invention as defined in the claims.
, Claims:WE CLAIM :

1. An electrical isolation network fire alarm control module adapted for controlling a plurality of fire alarm relays, with

a. each relay having a pair of normally closed contact (NC), one capable of being coupled to a fire damper and second capable of being coupled to AHU and with each rely also having a pair of normally open contact (NO) capable of being coupled to a source of power through the fire alarm control module,
b. wherein the operable power supply voltage of each of the plurality of associated fire dampers is not the same as the other,
c. wherein the AHU has a local control panel (LCP) with incoming lines and it has plurality of TAP off each operating at a specific voltage supply for tripping a fire damper operating at specific voltage supply, and
d. the said arrangement characterized in that each relay through its first NC contact adapted to trip a damper operating at a specific power supply only and each relay through its second NC contact of the relay is also adapted to be tripped by its corresponding AHU, such that fire dampers are triggered by tripping the supply AHU control panel instead of local tripping at each damper.