ASTM F1198-92(2023)

Standard Guide for Shipboard Fire Detection Systems

SIGNIFICANCE AND USE
4.1 The purpose of a shipboard fire detection system is to provide warning so as to reduce the life safety threat from fire and to minimize the fire threat to the operation of the ship. Given that few ships are identical either in size or layout, it follows that the fire detection system will have to be custom designed accordingly. A well-designed system provides a reasonable substitute to having crew members on constant fire watch in every protected space where a fire might occur.  
4.2 The basic function of the fire detection system is to automatically and reliably indicate a fire condition as quickly as is practical and to alert responsible individuals of a fire's existence and location. This system design and application guide addresses the individual steps in the layout of the system and provides an overview of the information needed to design a system.  
4.3 The U.S. Coast Guard and the International Convention for the Safety of Life at Sea (SOLAS) regulations have been stated as requirements within this guide. Additional guidelines to assure complete and effective systems or to incorporate good industry practices are stated as recommendations.
SCOPE
1.1 This guide covers the selection, installation, maintenance, and testing of shipboard fire detection systems other than sprinkler systems.  
1.2 This guide is intended for use by all persons planning, designing, installing, or using fire alarm systems onboard vessels. As it includes regulatory requirements, this guide addresses those vessels subject to regulations and ship classification rules. However, the principles stated herein are also suitable for unregulated commercial vessels, pleasure craft, military vessels, and similar vessels that are not required to meet regulations for fire detection and alarm systems.  
1.3 Limitations—This guide does not constitute regulations or ship classification rules, which must be consulted when applicable.  
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Nov-2023
• ICS: 13.220.20 - Fire protection
• ICS: 47.020.50 - Deck equipment and installations
• Technical Committee: F25 - Ships and Marine Technology
• Drafting Committee: F25.10 - Electrical

Relations

• Replaces: ASTM F1198-92(2018)e1 - Standard Guide for Shipboard Fire Detection Systems
• Effective Date: 01-Dec-2023
• Referred By: ASTM F1994-99(2023) - Standard Test Method for Shipboard Fixed Foam Firefighting Systems
• Effective Date: 01-Dec-2023

Overview

ASTM F1198-92(2023): Standard Guide for Shipboard Fire Detection Systems is an internationally recognized standard developed by ASTM International. This guide provides comprehensive best practices and recommendations for the selection, installation, maintenance, and testing of shipboard fire detection systems, excluding sprinkler systems. Its main goal is to enhance life safety and protect ships from fire hazards by ensuring reliable warning systems that enable early detection and prompt response.

Covering a diverse range of vessels, including regulated commercial ships, unregulated commercial vessels, pleasure craft, and military vessels, this standard supports stakeholders in designing customized fire detection setups that comply with the unique layouts and functional requirements of different ships. The guide references regulatory frameworks such as U.S. Coast Guard requirements and SOLAS (International Convention for the Safety of Life at Sea), and offers valuable guidance for compliance with international marine safety standards.

Key Topics

• Purpose of Fire Detection Systems: Shipboard fire detection systems are designed to promptly alert responsible personnel to fire incidents, enabling swift action to reduce threats to life and vessel operations.
• Types of Fire Detection Systems: The standard addresses various system types, including electrical automatic systems, manual alarm systems, pneumatic detection systems, sample extraction smoke detectors, and, to some extent, sprinkler systems.
• System Components: Key elements discussed include heat detectors, smoke detectors (ionization and photoelectric), flame detectors (IR, UV, or visible light detection), control panels, annunciators, and alarm signaling devices.
• Zone and Coverage Planning: Recommends dividing the ship into distinct fire detection zones for efficient system configuration and effective alarm response.
• Environmental Considerations: Emphasizes the importance of equipment selection based on shipboard environmental conditions such as humidity, temperature extremes, vibration, and electromagnetic interference.
• Regulatory and Classification Guidance: The guide does not serve as a direct regulatory document but references U.S. Coast Guard regulations, SOLAS requirements, and good industry practices for system approval and maintenance.
• Installation, Maintenance, and Testing: Offers recommendations for proper installation, regular maintenance, and testing protocols to ensure system reliability.

Applications

Shipboard fire detection systems are critical for:

• Commercial Shipping: Ensuring compliance with national and international maritime safety laws and minimizing operational downtime from fire incidents.
• Passenger Vessels: Safeguarding life and property where large numbers of people are at risk.
• Military and Government Vessels: Maintaining constant operational readiness and meeting stringent defense safety protocols.
• Unregulated Craft: Providing valuable guidelines for vessels not subject to mandatory fire safety rules, offering owners and operators a means to implement best practices voluntarily.
• Design & Retrofitting: Assisting naval architects, marine engineers, and installers in both new construction and retrofitting projects to address evolving layouts and integrate the latest technology.
• Ship Maintenance Teams: Offering a clear framework for ongoing system testing and troubleshooting, ensuring long-term reliability.

Related Standards

• SOLAS (International Convention for the Safety of Life at Sea): Core international marine safety agreement referenced throughout the guide.
• U.S. Coast Guard Regulations: Title 46, Part 76 (Fire Protection Equipment) and related sections for U.S.-flagged vessels.
• NFPA 72E: National Fire Alarm and Signalling Code for guidelines on detection equipment and spacing.
• Other ASTM Marine and Electrical Standards: For materials, installation quality, and environmental resilience.

These standards work together to support a unified, internationally compliant approach to shipboard fire protection, helping shipowners, operators, and crews maintain high safety standards and effective emergency response strategies.

Keywords: shipboard fire detection systems, ASTM F1198, SOLAS fire safety, marine fire alarm, vessel fire protection, U.S. Coast Guard fire regulation, marine safety standards, fire detection installation, fire detector maintenance, maritime fire alarm systems.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F1198 − 92 (Reapproved 2023) An American National Standard
Standard Guide for
Shipboard Fire Detection Systems
This standard is issued under the fixed designation F1198; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Title 46, Part 76.33
Title 46, Part 161.002
1.1 This guide covers the selection, installation,
2.2 NFPA Publications:
maintenance, and testing of shipboard fire detection systems
NFPA 72E Standard on Automatic Fire Detectors
other than sprinkler systems.
2.3 Safety of Life at Sea (SOLAS) Regulations:
1.2 This guide is intended for use by all persons planning,
SOLAS II-2/13-1
designing, installing, or using fire alarm systems onboard
SOLAS II-2/12
vessels. As it includes regulatory requirements, this guide
addresses those vessels subject to regulations and ship classi-
3. Terminology
fication rules. However, the principles stated herein are also
suitable for unregulated commercial vessels, pleasure craft, 3.1 Definitions:
military vessels, and similar vessels that are not required to
3.1.1 accommodation space, n—those spaces used for pub-
meet regulations for fire detection and alarm systems. lic spaces, corridors, lavatories, cabins, bunkrooms,
staterooms, offices, hospitals, cinemas, game and hobby rooms,
1.3 Limitations—This guide does not constitute regulations
barber shops, pantries containing no cooking appliances, and
or ship classification rules, which must be consulted when
similar spaces.
applicable.
3.1.2 alarm signalling device, n—an audible or visual de-
1.4 The values stated in inch-pound units are to be regarded
vice such as a bell, horn, siren, strobe, flashing, or rotating light
as standard. The values given in parentheses are mathematical
used to warn of a fire condition.
conversions to SI units that are provided for information only
3.1.3 annunciator, n—an audible and visual signalling panel
and are not considered standard.
that indicates and displays the alarm, trouble, and power
1.5 This standard does not purport to address all of the
conditions of the fire detection system.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1.4 approved, adj—acceptable to the organization, office,
priate safety, health, and environmental practices and deter- or individual responsible for accepting equipment, an
mine the applicability of regulatory limitations prior to use. installation, or a procedure.
1.6 This international standard was developed in accor-
3.1.5 automated machinery space, n—a space containing
dance with internationally recognized principles on standard-
machinery that is automated to allow: (a) periodic unattended
ization established in the Decision on Principles for the
operation by the crew; and (b) continuous manual supervision
Development of International Standards, Guides and Recom-
by the crew from a central room (enclosed) or remote location.
mendations issued by the World Trade Organization Technical
3.1.6 control panel, n—an electrical panel that monitors and
Barriers to Trade (TBT) Committee.
controls all of the equipment associated with the fire detection
2. Referenced Documents and alarm system.
2.1 Code of Federal Regulations: 3.1.7 control space, n—an enclosed space within which is
Title 46, Part 76.25 located a ship’s radio, main navigating equipment, emergency
Title 46, Part 76.30 source of power, or the centralized fire recording or fire control
equipment, but not including individual pieces of firefighting
This guide is under the jurisdiction of ASTM Committee F25 on Ships and equipment or firefighting apparatus that must be located in the
Marine Technology and is the direct responsibility of Subcommittee F25.10 on
cargo area.
Electrical.
Current edition approved Dec. 1, 2023. Published December 2023. Originally
ɛ1
approved in 1989. Last previous edition approved in 2018 as F1198 – 92 (2018) .
DOI: 10.1520/F1198-92R23. Available from National Fire Protection Association (NFPA), 1 Batterymarch
Available from U.S. Government Printing Office, Superintendent of Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:// Available from International Maritime Organization (IMO), 4, Albert
www.access.gpo.gov. Embankment, London, SE1 7SR, United Kingdom, http://www.imo.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1198 − 92 (2023)
3.1.8 hazardous (classified location), adj—locations where follows that the fire detection system will have to be custom
fire or explosion hazards may exist due to flammable gases or designed accordingly. A well-designed system provides a
vapors, flammable or combustible liquids, combustible dust, or reasonable substitute to having crew members on constant fire
ignitable fibers or flyings. watch in every protected space where a fire might occur.
3.1.9 listings, n—equipment or materials included in a list
4.2 The basic function of the fire detection system is to
published by an organization certified to perform product
automatically and reliably indicate a fire condition as quickly
evaluations. This organization maintains periodic inspections
as is practical and to alert responsible individuals of a fire’s
of production of the listed equipment or materials. The listing
existence and location. This system design and application
states either that the equipment or material meets appropriate
guide addresses the individual steps in the layout of the system
standards or has been tested and found suitable for use in a
and provides an overview of the information needed to design
specified manner.
a system.
3.1.10 machinery spaces of Category A, n—those spaces
4.3 The U.S. Coast Guard and the International Convention
and trunks to such spaces which contain: (a) internal combus-
for the Safety of Life at Sea (SOLAS) regulations have been
tion machinery used for main propulsion; or (b) internal
stated as requirements within this guide. Additional guidelines
combustion machinery used for purposes other than main
to assure complete and effective systems or to incorporate good
propulsion where such machinery has, in the aggregate, a total
industry practices are stated as recommendations.
power output of not less than 500 hp (375 kW); or (c) any
DESIGN AND APPLICATION
oil-fired boiler or oil fuel unit.
3.1.11 main vertical zones, n—those sections, the mean
5. System Types
length of which does not, in general, exceed 131 ft (40 m) on
any one deck, into which the hull, superstructure, and deck 5.1 Fire detection and alarm systems used on vessels are
houses are required to be divided by fire-resisting bulkheads. typically of the following types:
5.1.1 Electrical Automatic Fire Detection and Alarm
3.1.12 manually activated fire alarm box, n—a box contain-
Systems—These systems consist of a control panel, various
ing an electrical switch which, when manually operated, sends
types of fire detectors, manually actuated fire alarm boxes,
an alarm signal to the control panel (referred to as “Manually
audible and visual alarms, and appropriate power supplies. The
Operated Call Points” by SOLAS).
control panel monitors the fire detection and alarm circuits and
3.1.13 roll on/roll off cargo space, n—a space not normally
generates appropriate signals when an automatic fire detector
subdivided in any way and extending to either a substantial
or manual fire alarm box is activated.
length or the entire length of the ship in which cargo, including
5.1.2 Manual Fire Alarm Systems—A similar system with-
packaged cargo, in or on rail or road cars, vehicles (including
out automatic fire detectors is referred to as a manual fire alarm
road or rail tankers), trailers, containers, pallets, or demount-
system but is otherwise identical. Operation is initiated by
able tanks (in or on similar stowage units or other receptacles),
individuals who activate a manually actuated fire alarm box
can be loaded and unloaded normally in a horizontal direction.
that incorporates an electrical switch. This guide is primarily
3.1.14 self restoring, v—the ability of a device to reset itself
concerned with electrically operated automatic and manual fire
automatically after being activated.
detection and alarm systems.
5.1.3 Pneumatic Fire Detection Systems—These systems
3.1.15 service space, n—spaces used for galleys, pantries
consist of a closed length of pneumatic tubing attached to a
containing cooking appliances, locker rooms, mail rooms,
control unit. Air chambers called heat actuated devices (HADs)
specie rooms, store rooms, workshops other than those forming
are often attached to the tubing in the protected area to increase
part of the machinery spaces, and similar spaces, as well as
trunks to such spaces. the volume and thus the sensitivity of the system. As tempera-
ture builds up in a fire, the air in the tubing expands, moving
3.1.16 special category space, n—an enclosed space above
a diaphragm in the control unit. A small calibrated vent
or below the bulkhead deck intended for the carriage of motor
compensates for normal changes in ambient temperature. The
vehicles with fuel in their tanks for their own propulsion, into
diaphragm activates a release mechanism or a set of contacts.
and from which such vehicles can be driven and to which
Because pneumatic fire detection systems are self-contained
passengers have access.
(that is, independent of outside sources of power), they are
3.1.17 supervised, v—describes an electronic method of
often used to activate small automatic fire extinguishing
monitoring the electrical continuity of the circuits and devices
systems such as are installed in paint lockers and emergency
of a fire detection and alarm system. This is normally accom-
generator enclosures. U.S. Coast Guard Requirements for
plished by constantly passing a small current through the
pneumatic fire detection systems may be found in Title 46,
circuits and devices.
Code of Federal Regulations, Part 76.30.
5.1.4 Sample Extraction Smoke Detection Systems—These
4. Significance and Use
systems consist of a piping system connected to a control unit
4.1 The purpose of a shipboard fire detection system is to with a suction blower. These systems continually draw samples
provide warning so as to reduce the life safety threat from fire from the protected spaces to the control unit where a light
and to minimize the fire threat to the operation of the ship. source and photocell monitor the sample for smoke. Sample
Given that few ships are identical either in size or layout, it extraction smoke detection systems are often used in cargo
F1198 − 92 (2023)
holds because they are less likely than individual spot-type sponds when the temperature of the air surrounding the
smoke detectors to operate from dust or localized sources of detector reaches a predetermined level, regardless of the rate at
smoke such as vehicle exhausts. Also, the more delicate which the temperature rises. It is designed to avoid the thermal
electronics and control equipment can be located remote from lag time that is inherent in a fixed temperature detector. This
the harsh environment of a cargo hold. These systems are often device is also known as a rate anticipation detector.
combined with a carbon dioxide extinguishing system, using
6.5 Combination heat detectors take advantage of more than
the carbon dioxide distribution piping to draw samples from
one operating principle in a single detector housing. Combi-
the protected areas. Detailed requirements for sample extrac-
nation fixed temperature and rate-of-rise detectors are most
tion smoke detection systems are contained in proposed
common.
SOLAS Regulation II-2/13-1 and in U.S. Coast Guard regula-
6.6 Smoke detectors are devices that detect visible or
tions found in Title 46, Code of Federal Regulations Parts
invisible products of combustion. They work on several
76.33 and 161.002.
operating principles as follows:
5.1.5 Automatic Sprinkler Systems—Systems that are con-
6.6.1 Ionization smoke detectors have a small radioactive
stantly pressurized and connected to a continuous supply of
source that ionizes the air within a chamber, making it
water and fitted with a suitable means for automatically giving
conductive so that a small current flows between electrodes.
visual and audible alarm signals may also be considered to be
Smoke particles entering the chamber interfere with the free
fire (heat) detection and alarm systems. Detailed requirements
flow of ions and reduce the current, activating the detector.
are found in SOLAS Regulation II-2/12 and U.S. Coast Guard
6.6.2 Photoelectric smoke detectors use a light source and
Regulations, Part 76.25.
photocell to detect the presence of smoke. Several types may
6. Classification of Fire Detectors
be used on ships:
6.1 Heat detectors are devices that sense a fixed temperature
6.6.2.1 In the light obscuration type of detector, smoke
or rate of temperature rise. Heat detectors work on one of the
particles that enter between the light source and the photocell
three operating principles outlined in 6.2, 6.3, and 6.4.
reduce the amount of light reaching the photocell, causing the
detector to activate. Projected linear beam smoke detectors are
6.2 A fixed temperature detector is a device that responds
light obscuration smoke detectors. The light source and pho-
when its operating element becomes heated to a predetermined
tocell are separately housed, and the light beam is projected
level. Because of the time required to heat the mass of element
across the protected area. The alignment between transmitter
to its preset level, there is usually a lag time, referred to as the
and receiver is critical for proper operation of this device.
“thermal lag,” between the time the surrounding air reaches the
Shipboard vibration and flexing may affect proper alignment.
operating temperature and the time the operating element
6.6.2.2 In a photoelectric light-scattering smoke detector,
reaches its preset operating temperature. There are seven
the components are arranged so that light does not normally
temperature classification ranges. In locations where the ceil-
reach the photocell. When smoke particles enter the chamber,
ing temperature does not exceed 100 °F (38 °C), detectors with
they reflect or scatter some of the light onto the photocell,
an operating range of 135 °F to 174 °F (57.2 °C to 78.9 °C)
activating the detector.
should be used. These are termed “ordinary” temperature
6.6.3 Sample extraction smoke detection systems as de-
classifications. Several types of temperature-sensitive operat-
scribed in 5.1.3 operate on one of the principles covered in
ing elements are used, such as:
6.6.2.1 and 6.6.2.2.
6.2.1 Bimetallic elements, which consist of two metal strips
with different coeffıcients of expansion fused together so that
6.7 Flame detectors are devices that detect infrared (IR),
heating will cause the element to deflect, making electrical
ultraviolet (UV), or visible light produced by a fire. To avoid
contact.
activation by sources or radiation other than fires such as
6.2.2 Electrical conductivity elements, which are devices
welding, sunlight, and so forth, flame detectors are usually
whose electrical resistance varies as a function of temperature.
designed to sense light modulated at a rate characteristic of the
6.2.3 Certain automatic heat detectors use fusible alloy
flicker rate of flames, or to detect certain bands of IR or UV or
elements or liquid expansion elements that operate at a fixed
visible radiation characteristic of flames, or some combination
temperature. These devices are nonrestorable and are prohib-
of these features. A combination of these features is used in
ited by SOLAS.
some applications to reduce the probability of false alarms.
6.3 A rate-of-rise detector is a device that operates when the
6.8 Other classifications of fire detectors include: (a) gas
temperature rises at a faster than predetermined rate. Since
detectors that sense gases produced by burning substances; (b)
operation does not depend on having reached a fixed tempera-
resistance bridge smoke detectors that sense change in conduc-
ture level, it responds to a rapid temperature rise more quickly
tivity when smoke particles and moisture from fire are depos-
than a fixed temperature detector. However, it does not respond
ited on an electrical grid; (c) cloud chamber smoke detectors in
to a slow developing fire regardless of how high the tempera-
which moisture is caused to condense on smoke particles
ture gets. In a typical rate-of-rise detector, heated air in a
drawn into a chamber; and (d) heat-sensitive cable in which
chamber expands to deflect a diaphragm that operates electric
high temperature softens the insulation separating two
contacts.
conductors, causing reduced resistance or shorting of the
6.4 A rate of compensation detector is a device which, conductors, as well as devices that operate on other principles.
because of differential expansion of several components, re- Such detectors are seldom used on ships.
F1198 − 92 (2023)
6.9 Combination detectors combine the principles of one or 9.2 Manufacturers shall be able to provide documentation
more classifications of fire detectors or detection principles in and certification indicating the effect that environmental con-
a single device. A common example is a fixed temperature- ditions such as temperature, humidity, pressure, air velocity,
rate-of-rise heat detector. and electromagnetic interference (EMI), including radio fre-
quency (R.F.), transients, corrosives, dust, and vibration, can
6.10 All detectors, except sprinklers, are required by regu-
have on detector sensitivity and performance.
lation to be restorable so that they can be tested for correct
operation and restored to normal condition without replacing
9.3 Testing standards for detectors are usually minimum
any component.
standards and, therefore, listed detectors are not all equal in
performance. For example, smoke detectors may respond to
7. System Detector Coverage
smoke densities ranging from 0.5 % ⁄ft to 4 % ⁄ft obscuration.
7.1 Existing U.S. and international regulations for commer-
All smoke detectors are marked with their sensitivity. A
cial vessels require automatic fire detection coverage in a wide
detector with a 1 % ⁄ft obscuration is more sensitive than a
range of spaces such as corridors, stairways, escape routes
detector set at 3 % ⁄ft. A 3 % ⁄ft obscuration may prove more
from accommodation spaces, RO-RO cargo spaces, and auto-
stable than a detector at 1 % ⁄ft obscuration level. An engineer-
mated machinery spaces.
ing judgement shall be made as to which sensitivity is more
acceptable for which application.
7.2 It is recommended that each accommodation space have
detector coverage, including a detector in each stateroom.
9.4 Temperature:
Consideration should also be given to placing detectors in other
9.4.1 Smoke detectors placed in areas with temperatures
normally unattended areas where a fire may originate.
approaching the upper or lower limits of the testing laboratory
listing will undergo a shift in sensitivity as a result of those
7.3 In addition to detectors, manually actuated fire alarm
boxes must be installed throughout passageways of the temperatures. Detector sensitivities will not shift equally; some
detectors will change little and others will change more. The
accommodation, service, and control spaces and be located at
each main exit and stairwell exit. Manually actuated fire alarm design and quality of the detector can make a difference in
performance.
boxes are also required in all special category spaces.
9.4.1.1 Generally, ionization detectors become either more
8. Zoning
sensitive in colder temperatures or less sensitive in warmer
8.1 The fire detection system should be arranged into
temperatures.
reasonably sized and clearly identified areas, called zones, to
9.4.1.2 Generally, photoelectric detectors become either less
direct responding crew members to the fire’s location more
sensitive in colder temperatures or more sensitive in warmer
quickly. Consideration should be given to having two detection
temperatures.
circuits within a zone (that is, area or space). One detection
9.4.1.3 Flame detectors vary according to individual design.
circuit should be dedicated to manually actuated fire alarm
See the manufacturer’s information.
boxes and the other dedicated to automatic fire detectors so that
9.5 Relative Humidity (RH)—Relative humidity levels up to
alarms can be distinguished from each other. Existing require-
95 % should not affect the performance of most detectors.
ments limit individual detection zones as follows:
However, condensate can present a problem to the stability of
8.1.1 A zone is limited to a single deck level, except where
the detectors. Curves and documentation on the effects of
an enclosed stairway is served by an individual detection zone.
relative humidity can be obtained from manufacturers of
This zone can include multiple deck levels. Where the stairway
detectors.
is used as a main egress in the event of a fire, it is recom-
mended that a stairway which joins four or more levels be
9.6 Air Pressure:
served by a separate zone.
9.6.1 Except for ionization detectors, atmospheric pressures
8.1.2 In passenger ships, separate zones are required on the
usually have no measurable effect on detector sensitivity. For
port and starboard sides of the ship; however, regulations
unusual circumstances, such as submarines or pressure
permit exceptions for special cases. Detection zones must be
chambers, refer to the manufacturer’s data.
confined horizontally to one main vertical zone (MVZ).
9.6.2 Ionization detectors become less sensitive with a
8.1.3 Enclosed automated machinery spaces must be sepa-
decrease in pressure and more sensitive with an increase in
rately zoned from accommodation, service, and control spaces.
pressure. Curves and other documentation on the effects of
Multiple small machinery spaces in the same general area may
pressure on detector sensitivity can be obtained from the
be grouped into a single zone. Clearly identify which connec-
manufacturer, testing laboratory, or both.
tions are to be made to the equipment being monitored.
9.7 Air Velocity:
9. Environmental Effects on Detectors
9.7.1 Continuous high air velocities or sudden gusts are
major factors influencing the stability of some ionization
9.1 Because ships are able to move freely throughout the
detectors and may cause false alarms or delayed alarms.
world, they can be subjected to many different environmental
Curves and documentation on the effects of air velocities on
conditions. This makes it very important that the selection
detector sensitivity can be obtained from the manufacturer.
process of detectors, control panels, and other alarm system
components be made by data and information available from 9.7.2 Some detectors use field adjustability to compensate
manufacturers and testing laboratories. the detector for sensitivity shifts caused by air velocity.
F1198 − 92 (2023)
9.7.3 Some detectors use optional air shields to reduce the 10.2.1 Determine the maximum detector spacing for
effects of air velocity on detector sensitivity. smooth, low ceilings and no air flow.
9.7.4 Photoelectric detector sensitivities are not affected by 10.2.1.1 Listings or approvals show maximum spacing dis-
air velocity. tance between detectors.
10.2.1.2 Distances are determined by fire tests with proto-
9.8 Electromagnetic Interference (EMI)—RF energy from
type detectors.
sources such as walkie talkies, telephones, and so forth may
10.2.2 For rooms over 10 ft (3 m) high, reduce thermal
cause false alarms in ionization and photoelectric detectors.
detector spacing according to Table 2. Add intermediate layers
Documentation as to the levels of EMI and at what distances
of detectors for spaces over 30 ft (9 m) high. For other
these energies are safe to use around detectors can be obtained
classifications of detectors, reduced spacing should be consid-
from the manufacturer, testing laboratory, or both.
ered as vertical height increases. Consult the manufacturer for
9.9 Other factors influencing the reliability and stability of a
specific requirements.
detector are as follows:
10.2.3 To determine the minimum number of detectors, set
9.9.1 Unusually high concentrations of vapors from sol-
up a grid of squares using the adjusted maximum spacing with
vents and paints, aerosol sprays, steam, smoke products from
a detector at the center of each square.
kitchens, and tobaccos are some environmental contaminants
10.2.4 Adjust the detector locations to avoid air diffusers,
that may cause false alarms to smoke detectors.
which may blow heat and smoke away from detectors.
9.9.2 Cigarette lighters, welding, reflection of sunlight, and
10.2.5 Verify that no point in the space is more than 0.7
lightning are some of the environmental conditions that can
times the reduced maximum spacing distance horizontally
prove troublesome for UV and IR flame detectors.
from the nearest detector.
9.9.3 In sele
...