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Fire Alarm PCB: The Ultimate FAQ Guide

Table of Contents

This guide will answer all questions you have about fire alarm PCB.

So, before choosing your next fire alarm PCB, read this guide.

Let’s dive right in.

What Are The Uses Of Fire Alarm PCB?

Fire alarm PCB
Fire alarm PCB

Fire alarm PCBs are majorly used to caution people immediately they detect fire, smoke and other tragedies that are fire-related.

The fire alarm PCB automatically activates an alarm based on the reaction of heat and smoke detectors for further preventive action.

They can also be enjoined as part of a multifaceted home security system together with other security-related parameters like motion detectors and intruder alert.

What Is The Role Of NE555 Timers In Fire Alarm PCB?

The core of a fire alarm PCB is the 555 timer integrated circuit.  The integrated circuit has a frequency of oscillation that ranges from 670Hz-680Hz.

The NE555 timer behaves as a multivibrator that is astable. This is an oscillator that is free-running and continuously switches between its dual unstable states.

When there is no external applied signal, the transistor will interchangeably switch from saturation state to cutoff.

This is at a frequency determined by the RC time coefficients of the coupler circuits.

If the time coefficients are the same (C and R are equal), a square wave will be produced bearing a frequency of approximately 1/1.4 RxC.

This shows that an astable multivibrator can also act as a square wave generator or a pulse generator.

How Can You Increase The Sound Of Fire Alarm PCB Device?

The volume in a fire alarm PCB is very crucial as a warning parameter. The normal sound capacity of a fire alarm PCB is between 30 to 50 decibels.

This can be greater depending on the environment of placement of fire alarm PCB e.g. restaurant or public places.

Safety and fire codes dictate that no adjustments can be effected on an already installed fire alarm PCB.

This is a safety requirement that must be complied with.

Tampering with a fire alarm PCB has penalties and can be classified as a criminal liability. However, its proximity to hearing distance increases the sound hence placement is a major factor.

What Are The Recommended Base Materials For Fire Alarm PCB?

Americum 241 which is a radioactive isotope has been the preferred base material for fire alarm PCBs. This is an extremely stable material with estimated half-life of 458 years.

It is normally sealed within silver and gold foils after being processed with gold.

Of course, depending on the application at hand, you can choose a range of PCB materials such as:

PCB Material
PCB Material

Which Are The Common Fire Sensors Used In Fire Alarm PCB?

There are various types of sensors used in a fire alarm PCB depending on functionality and design. The major sensors in use include:

Ionization Sensor

These kind of sensors have a continuous electrical current that runs between two dual plates located inside the sensor.

The flow of current is disrupted when smoke goes into the chambers of the device thus triggering an alarm.

Such kind of sensors are suitable for effectively identifying fast-burning fires.

Photoelectric Sensor

These kind of sensors works in a comparable manner to ionization sensors but instead of an electric current, it utilizes a beam of light.

The light beam becomes scattered immediately smoke finds its way into the sensors chamber.

This leads to the alarm being triggered. This type of sensor is suitable for detecting smaller fires.

Photoelectric sensors are exceedingly dependable and they seldom produce false alarms.

Ionization/Photoelectric Sensor

This combination of photoelectric and ionization sensors is thought to be the best based on many professionals.

This type of sensor combination ensures that even the slightest occurrence of smoke is noticed at the earliest instance.

Heat Sensors

Heat sensors mode of operation is by detecting variations in the air temperature brought about by fire.

In as much as such detectors are infamous for several false alarm triggers, their reaction time is longer than the other smoke sensors.

Such sensors are suitable for premises that are infrequently used like storage facilities or warehouses.

This is because false alarms are normally triggered in premises that are unusually moist, humid or dusty.

How Many Sensors Should You Include In Fire Alarm PCB Assembly?

In order to achieve a dependable early fire detection with marginal false alarms and over an extensive array of applications, as many sensors as possible should be utilized.

This is because unwanted alarms are brought about detection of smoke-like occurrences in the service environment like dust, aerosol and steam.

The more sensors are utilized in a fire alarm PCB, the less the chances of false fire alarms form collective causes such as dust, aerosol sprays and steam.

A multi-sensor fire alarm PCB utilizes several sensors such as carbon monoxide, smoke or heat to the presence of fire.

In general, it has been proven that the more detailed the sensors are on a fire alarm PCB, the less likely they were to cause regular false alarms.

This is without interfering with their ability to detect actual fires.

What Is The Preferred Copper Thickness Range For Fire Alarm PCB?

Assembled fire alarm PCB
Assembled fire alarm PCB

A fire alarm PCB requires specific copper thickness based on its design and specifications in order to accommodate the current load.

Copper thickness can be described as the weight of copper available in a square foot of area.

An appropriate thickness of copper for fire alarm PCB can be selected to match the design requirements. Examples include;

  • 5µm – this is the standard copper thickness of the internal layers of fire alarm PCB on request. It is classified as “non-standard” construction. It is also the external layers starting weight.
  • 35µm – this is the average internal thickness of the copper layer.
  • Other thickness – additional copper weights can be included upon request by the client to the fabricator. This is common in custom made fire alarm PCB.

Can You Fabricate Fire Alarm PCB With Thermistor?

Fire alarm PCB circuit with thermister
Fire alarm PCB circuit with thermister

Thermistors can be described as elements that sense temperature.

They consist of semiconductor material that are responsive to variations in resistance in relation to minor changes in temperature.

The thermistor utilizes heat detection to activate the fire alarm PCB. The alarm is triggered once a high temperature is detected by the thermistor.

The detection of temperature via thermistor does not require to be activated by smoke hence there are very few false alarms.

Besides, the thermistor uses a buildings and ambient temperature and can only be triggered with an exponential increase in that temperature.

Fabricating fire alarm PCBs with thermistors is a very reliable method because it has a faster alert rate with very few false alarms. It also versatile due to its many available placement options.

How Do You Check For Errors In Fire Alarm PCB Design?

It can prove challenging finding the root cause of errors in a fire alarm PCB. Most of the errors occur due to the following reasons:

Ground Faults

A ground fault takes place when an electrical component is short circuited to a grounded potential.

In a fire alarm PCB, it takes place when a wire is exposed or components of the PCB touch a grounded metal object.

Grounded metal objects near a fire alarm PCB may include ceiling grids, junction boxes or any other metallic objects.

On a normal operation mode, the fire alarm PCB directs a trouble signal to its annunciator displaying that a ground fault has occurred within the system.

While doing repairs on the fire alarm PCB, a ground disable jumper is used during trouble shooting to mute the annunciator.

This can accidentally be left after maintenance leading to ground faulting.

Ground faults can also be caused by poor wiring of fire alarm PCB installation such attaching the wires to all-thread hangers or premise structures.

Over time, the buildings natural vibration leads to wearing out of the wires and they ultimately get in contact with a ground potential.

Circuit Problems

This can be due to various reasons. Majorly, it is broken or disconnected wiring within the fire alarm PCB.

This leads to open circuits and fire alarm PCB malfunction.

Resistors become faulty from time to time depending on the environment that the fire alarm PCB is placed in.

It is advisable to always be checking the end line of the resistor regularly.

Loop trouble can also occur when the fire alarm PCBs data communication link is interrupted. This occurs due to fire alarm PCB failure or a short or open circuit.

Recommended Wire Types

Due to the sensitive nature of the fire alarm PCB, using the wrong connecting wires my lead to a variety of errors in its efficiency.

Two types of wires used in fire alarm PCB are power limited and non-power limited power fire alarm cables.

The least expensive power limited cable is he FPL cable.

FPLR shielded has the same constituents as the FPL but with an additional drain wire and aluminum foil that protects it against external interference.

NPLF is a non-power limited cable that’s recommended for use in general fire alarm PCBs.

Their application is however not suitable for use in plenum spaces, ducts or risers used in environmental air flow.

Another non-power limited fire alarm PCB cable is the NPLFP which is the most appropriate for duct and plenum installations.

Addressable fire alarm PCB
Addressable fire alarm PCB

What Is The Ideal Input Voltage Of Fire Alarm PCB?

The power supply of a fire alarm PCB requires two sources, the battery and the mains. The optimum input voltage should be 24V.

If operating on a battery, the standby batteries should be sufficient enough to allow at least 24 hours of operation without the mains.

In the event that the mains is complemented by a standby emergency generator, then it should run for 6 hours with an additional 30 minutes for alarm load.

Based on the fire alarm PCB design, some batteries will not fit within the fire alarm PCB compartment.

In such a scenario, the placement of the batteries should be as close as possible to the main fire alarm PCB.

Serious voltage drop may occur if the battery or power supply is located beyond 10 meters from the main fire alarm PCB.

The standby batteries should most preferably be in the variety of sealed lead acid.

Can You Manufacture Multilayer Fire Alarm PCB?

Fire alarm PCBs can be multilayered with more than four layers of copper foils embedded in several laminate layers.

Electrical connections are achieved via various vias placed on the fire alarm PCB multi-layers.

Multi-layer fire alarm PCBs have the advantage of having flexibility and a higher assembly density. The technology applied in fabrication makes the fire alarm PCB smaller and lighter.

Besides, the multi-layered fire alarm PCB has an improved performance compared to other single or multi-layered PCBs.

The multi-layers eliminate problems like noise, stray capacitance and crosstalk.

Which Is Better Between Conventional Fire Alarm PCB Device And Addressable Fire Alarm PCB Device?

Conventional fire alarm PCB devices utilize analogue technology. They comprise of multiple zones.

A zone is made up of multiple devices including notification and initiating devices make up a zone which is linked to the main panel.

The use of electrical currents for communication with the control panel makes it analogue.

Also, the current in conventional fire alarm PCB is increased by the notification and initiating devices anytime heat or smoke exceed a preset threshold.

Addressable systems rely on digital technology to convey data to the key control panel in form of binary code.

Deviations of voltage within the signal device create an analog signal that marks the start of the binary code.

Even in the modern digital world, preference is given to conventional fire alarm PCBs because they are affordable, dependable and cost-effective for small building use.

However, recent trends give more consideration to addressable systems when replacing fire alarm PCBs.

This is because of the additional technological benefits that is provided by the addressable fire alarm PCBs.

It may be costlier than the conventional fire alarm but the benefits in advancement of its technology outweigh the cost.

False alarms are mostly experienced with conventional fire alarm PCBs due to accumulation of contaminants and dust on the sensors.

These have an effect of sending incorrect signals to the control panel.

In contrast, a variety of data is sent by the addressable fire alarm PCB device to the control panel. These include maintenance alerts and trouble signals.

The alarm panel in addressable fire alarm PCBs observers the level of sensitivity of the smoke detectors. This helps in the prevention of false alarms.

How Should You Specify Fire Alarm PCB To Your Supplier?

When seeking a fire alarm PCB, the following specifications should be availed to the supplier;

  • Supply voltage – the supply voltage of the premise that the fire alarm PCB is going to be placed should be provided during fabrication.
  • Maximum Power supply unit (PSU) rating – this is given in amperes and also includes the battery charger rating.
  • Internal and external loads – this includes the systems nominal load and the maximum loop load.
  • Environmental operating limits – these include the nature of operations of the premise where the fire alarm PCB is to be installed and the prevailing weather conditions.
  • Internal sounder – they include intermittent buzzer and continuous high pitched buzzer.
  • External outputs – sounder programmable outputs should be specified. The auxiliary relays and changeover outputs should also be defined.

How Does Thermistor Fire Alarm PCB Device Operate?

Fire alarm relay PCB
Fire alarm relay PCB

Thermistors can be described as elements that sense temperature.

They consist of semiconductor material that are responsive to variations in resistance in relation to minor changes in temperature.

The thermistor utilizes heat detection to activate the fire alarm PCB. The alarm is triggered once a high temperature is detected by the thermistor.

Besides, the detection of temperature via thermistor does not require to be activated by smoke hence there are very few false alarms.

The thermistor uses a buildings and ambient temperature and can only be triggered with an exponential increase in that temperature.

Fabricating fire alarm PCBs with thermistors is a very reliable method because it has a faster alert rate with very few false alarms.

It also versatile due to its many available placement options.

They can be placed in:

  • Industrial premises containing a lot of smoke and dust
  • High steam areas such as dairy industries
  • Ovens and incinerators with a lot of gathered smoke
  • High temperature rooms like welding workshops

Why Should You Opt For ODM Manufacturing Of Fire Alarm PCB?

ODM (Original Design Manufacturing) is a very favorable and special kind of manufacturing procedure.

Here, help is sought from an established ODM fabricator whose project designs are already in existence.

Some of the benefits of using Original Design Manufacturing for fire alarm PCB include:

  1. This kind of manufacturing process saves money and time.
  2. The ODM manufacturer takes full responsibility in designing reliable and successful design products
  3. It is a very fast and swift way of establishing and selling one’s products.
  4. It is a very economical manufacturing method.
  5. Full attention can be paid to some simple operations that can make the ODM design efficient and exclusive.

What Is The Difference Between OEM And ODM In Fire Alarm PCB Fabrication?

Inductive smoke alarm
Inductive smoke alarm

Original Equipment Manufacturing (OEM)

Original Equipment Manufacturing (OEM) refers to fire alarm PCBs that are designed by a single company. The company then licenses the fire alarm PCB design to a manufacturer to produce.

The major benefit of OEM is that total innovative control of the design remains with the designer. OEM fire alarm PCBs can be fabricated to any specifications hence the designer’s creativity is the only limiting factor.

The demerit of OEM manufactured fire alarm PCB is that it is very resource intensive.

Heavy investment is put into research and improvement over a long period of time in order to come up with an exclusive fire alarm PCB design.

This means that OEM fire alarm PCB designs need to be protected as intellectual property.

Original Design Manufacturing (ODM)

Original Design Manufacturing (ODM) is where a client selects a pre-existing fire alarm PCB design from the manufacturer.

The client then makes a few adjustments and changes then sells the fire alarm PCB under their own name.

The benefit of ODM is that it saves the fabricator money used for the research and development of the design in creating a new fire alarm PCB from scratch.

By removing or greatly decreasing the product development cost, more focus can be put in marketing the fire alarm PCB.

The drawback of ODM is that it becomes difficult distinguishing between one’s fire alarm PCB design and other similar ones.

Also, the competition in pricing of ODM fire alarm PCBs is stiff hence resulting in lesser profit margins.

How Much Does It Cost To Manufacture A Piece Of Fire Alarm PCB In China?

The cost of manufacturing a fire alarm PCB is determined by very many factors.

Besides, the cost of materials plays a major role in determining the price.

Remember, the design specifications of the fire alarm PCB by the client will also play a major role in determining the price.

This includes number of layer stacks specified and the size.

The minimum order quantity also affects the price. A higher order will attract a reduction in price per unit as an incentive.

What Is Your Minimum Order Quantity (MOQ) For Fire Alarm PCB?

Depending on the fire alarm PCBs fabricators, the minimum order quantity may vary from a minimum of one unit to an indefinite maximum.

Various factors are considered when determining the minimum order quantity of a fire alarm PCB.

The demand for the design of the fire alarm PCB plays an important role in determining MOQ. Demand is influenced by factors like competition and seasonality.

The fabricators of fire alarm PCB also consider their beak-even when determining the minimum order quantity of fire alarm PCB.

Remember, the lowest per unit order is usually considered for a higher order value.

The fire alarm PCB fabricator can also decide to incentivize a higher MOQ hence reducing the cost per unit.

At Venture, we will design, fabricate and assemble high performance fire alarm PCBs.

For any questions or inquiry on fire alarm PCB, contact us now.

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