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Hochiki's SIL Approved Range

A guide to Hochiki's SIL Approved Product Range

What is SIL?

SIL is an acronym for Safety Integrity Level, and is a system used to quantify and qualify the requirements for Safety Instrumented Systems.

The International Electro-technical Commission (IEC) introduced the following industry standards to assist operators with quantifying the safety performance requirements for hazardous operations:

IEC 61508
Functional Safety of Electrical/Electronic/
Programmable Electronic Safety-Related Systems

IEC 61511
Safety Instrumented Systems for the Process Industry Sector

These standards have been widely adopted in the hydrocarbon and oil and gas industries as a means of improving safety and availability of Safety Instrumented Systems.

Safety Integrity Levels are part of a larger scheme called Functional Safety that deals with techniques, technologies standards and procedures that help operators protect against hazards. Simply put, SIL levels are targets applied to the reliability and performance of the safety systems used to protect hazardous activities such as hydrocarbon refining or production.


SIL2 Range inlcudes Intelligent and Conventional products


SIL Levels

There are four SIL levels. The higher the perceived associated risk, the higher the performance required of the safety system and therefore the higher the SIL rating number.

The IEC standards define the performance requirements of the safety systems for the required SIL rating.


How SIL Levels are Calculated

Once the scope of an activity is determined, the operator can identify the possible hazard(s) and then assess their potential severity. The risk associated with a hazard is identified by assessing the likely frequency of occurrence and the potential consequences if the
hazard is realised.

The operator must then assign a number for the severity of consequence and frequency.

Hazardous Activity Chart

The figure above shows multiple layers of protection are used to develop the required safety strategy. Safety Instrumented System has been highlighted because this is the layer that applies to Hochiki’s SIL 2 approved fire detection equipment.

The SIS assists in reducing the frequency of the likely manifestation of the hazard and therefore improves the reliability of the system. The consequence of a failure is not addressed by SIS but by other aspects of the risk reduction strategy.


These numbers are then entered into a matrix (see example below) to allow the operator to assign the required SIL rating to protect against the hazard.

Many tools are available to assist an operator with this process, for example HAZOP (Hazard & Operability) software.

SIL Matrix Example

Our SIL 2 approved range of products has been independently assessed by Engineering Safety Consultants Limited and is considered capable for use in a SIL 2, low demand Safety Function with regard to random failure rates.

Individual certificates are available to download from
our web site.



Our Current SIL2 Approved Products


Addressable Multi Sensor

The ACC-EN/SIL has 3 modes, which are controlled from the Control Panel, allowing either the optical element or thermal element or both elements to be active in making the fire decision. The sensor polling LEDs can be controlled via the Control Panel (pulsing/non-pulsing).

The ACC-EN/SIL smoke chamber can esily be removed or replaced for easy maintentance.

ACC-EN/SIL and ACC-EN(WHT)/SIL multi sensors

Addressable Smoke Sensor

The ALN-EN/SIL incorporates Hochiki’s newest High Performance Chamber Technology removing the need to use Ionisation Smoke Sensors in the majority of applications.

This also allows the sensor threshold level to be increased, thereby improving the signal to noise ratio and reducing susceptibility to false alarms.

ALN-EN/SIL and ALN-EN(WHT)/SIL - addressable smoke sensors

Addressable Multi Heat Sensor

The ATJ-EN/SIL incorporates a variable temperature heat element and a rate of rise heat element, both of which are controlled from the Control Panel, allowing either thermal element or both elements simultaneously to be active in making the fire decision.

ATJ-EN/SIL and ATJ-EN(WHT)/SIL - multi heat sensor

Conventional Manual Call Points

The CCP-E-IS/SIL is a conventional call point based upon the industry standard KAC world series housing, and which can be used in hazardous areas.

The CCP-W-IS/SIL is an IP67 version, for use externally.

CCP-E-IS/SIL and CCP-W-IS/SIL - conventional manual call points

Various Functions

Our Addressable Modules provide a range of functions, providing an interface between the loop and a host of third party equipment.  The majority of our modules feature an integral short-circuit isolator and are available in either an enclosed boxed version or a DIN rail mountable version.

The complete list of SIL2 Approved modules:

CHQ Modules and DIN Modules
    I. S. Compatible Sounder Controller
    Plant Control Module
    Dual Input Monitor
    Dual Relay Controller

Conventional I.S. Detectors 

The DCD-1E-IS/SIL is an Intrinsically Safe Conventional Rate of Rise Heat Detector with a 60° fixed temperature element designed for use in hazardous areas.  The unit also features a remote indicator output.

Model SLR-E-IS/SIL is a Photoelectric Smoke Detector designed for use in hazardous areas which also incorporates a remote indicator output and a removable chamber for easy maintenance.

DCD-1E-IS/SIL and SLR-E-IS/SIL conventional I.S. detectors

Addressable Wall Sounders/Beacons

Model CHQ-WS2/SIL is an addressable loop powered Wall Sounder innovatively designed to provide a range of tones and volumes with a maximum output of up to 102dB(A) (±2dB(A)) with low current consumption.

The CHQ-WSB2/SIL range comprises of EN54-23 compliant addressable loop powered Wall Sounder Beacon ias per the CHQ-WS2/SIL but with the addition of an integral LED beacon.

CHQ-WS2/SIL and CHQ-WSB2/SIL - addressable wall sounder/beacon

Addressable Base Sounder/Base Sounder Beacons

Model YBO-BS/SIL is an addressable loop powered Base Sounder innovatively designed to give a range of tones and volumes with a maximum output of up to 98 dB(A) (±2 dB(A)) with low current consumption

The YBO-BSB2/SIL range consists of ‘O’ Rated EN54-23 compliant addressable loop powered Base Sounders, with integral Beacon, givng a red or white flash.

YBO-BS/SIL and YBO-BSB2/SIL - addressable base sounder and base sounder beacon

Addressable Manual Call Points

Model HCP-E(SCI)/SIL is a Manual Call Point with integral short-circuit isolator, which is fully compatible with Hochiki’s ESP analogue addressable protocol.  The unit incorporates a bi-coloured LED

Model HCP-W(SCI)/SIL is a weatherproof Manual Call Point with integral short-circuit isolator, which is fully compatible with Hochiki’s ESP analogue addressable protocol.

HCP-E(SCI)/SIL and HCP-W(SCI)/SIL - addressable manual call points


Addressable Mounting Base

Model YBN-R/3(SCI)/SIL is a sensor mounting base featuring an integral short-circuit isolator which will detect and isolate short-circuits on the loop. When a short-circuit is detected during power up the unit will drop the power to the rest of the loop.

YBN-R/3(SCI)/SIL and YBN-R/3(WHT)-SCI/SIL - mounting bases



Learn More

There is a SIL Overview document available, portions of which make up this web page, which is free to download from the PDF icon, right. 

For any SIL related enquiries, please drop us a line using the enquiry form below.

Learn more about our SIL offering, download our FREE overview



For almost 100 years Hochiki has led the way in the design and manufacture of innovative life safety solutions. Its leading edge commercial and industrial fire detection and emergency lighting products have acquired global acceptance as the benchmark for high-integrity and long-term reliability.

With a global sales turnover exceeding £400m Hochiki is a wholly independent, multinational, publicly listed company with over 1,500 employees working across five manufacturing plants, 32 sales offices and 18 subsidiaries.

Its ongoing commitment to manufacturing innovation ensures customer satisfaction and its production facilities in Japan, the USA and Europe offer international continuity in quality, service and supply.

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