# Directional Sound Evacuation

- Marine

What is Localizer ® 

### technology?

Fire Safety

Fire at Sea

Confusion in smoke

Signs lost in smoke In the context of Marine safety, Directional Sound Evacuation (DSE) has the following advantag es:

- Language independent

- “Audible exit signs”

- up to 75% improvement in exit times

- Time saved = Lives saved

- Ideal in poor visibility (dense smoke)

- Lower cost

– easy retrofit

- Works in open areas, corridors, stairs

- ADA & DDA conform ance

Localizer

® 

### directional sound is a broadband, multi

- frequency (“white noise”) sound. The sound source is easily and quickly located by our ears, making it ideal for rapid ship evacuation. Details of the technology and the wide variety of applications can be found on the website www.soundalert.com

Developed at Leeds University, the technology is patented in the UK, USA, Australia and Hong Kong, with applications being processed in EU, Canada and Japan.

Conventional General Alarm sounders and PA syst ems efficiently warn people in the event that evacuation is necessary, but can give no indication of exit routes. Illuminated exit signs and low location lighting will help only if visible and not obscured by smoke. Localizer

- equipped DSE evacuation beaco ns can identify the nearest evacuation routes even in dense smoke. DSE was recently awarded the Fire Industry Council’s product innovation award and the RINA~Lloyds Register of Shipping Safer Ship award

The Scandinavian Star disaster showed that rapid eva cuation of the smoke

- filled areas would have saved lives. Low

- Location Lighting has limitations in smoke filled environments where visibility is severely restricted

– the recent Nieuw Amsterdam incident illustrated this. LLL gives no indication of directi on to the nearest exit and is ineffective in open spaces. Normal wisdom is that evacuees should crouch and follow the evacuation route at floor level. However, whilst hot smoke rises in a stable still atmosphere, it quickly fills down to floor level when c ooled by water mist extinguishing systems or disturbed by ventilation systems and people movement.

Directional sound technology offers an additional or alternative evacuation method giving audible assistance that can considerably improve exit times. Loc alizer evacuation beacons positioned at carefully chosen locations guide people along escape routes. In addition to corridors and stairs, Localizer can also guide people out of open spaces, which represent as much as 40% of modern passenger ships, and toda y have no evacuation aids effective in smoke.

The UK Government’s Maritime & Coastguard Agency recently completed an extensive series of independent tests with University of Strathclyde in which over 400 volunteers participated in trials simulating accom modation, corridors, stairs and open spaces with and without smoke. In these trials improvements of up to 75% in evacuation times were recorded in smoke and 35% in perfect visibility. Following these trials, the Governments of UK and Germany are proposing Directional Sound Evacuation to the United Nations’ IMO for approval within SOLAS regulations as an alternative to Low Location Lighting and mandatory fitment in open spaces. In May 2002, IMO’s Maritime Safety Committee commented: “directional sound is at least as effective as Low Location Lighting and its use is not diminished by smoke”. Full details on the MCA’s website: www.directionalsoundevacuation.com

Implementation can be proposed using the new SOLAS Chapter II

- 2 Regulation 17 “Alternative design & arrangements” for a “case by case” approval.

Systems can be installed today as an extension to existing PA/GA systems and hence require no additional type approval.

* The Localizer is the registered trademark of Sound Alert Technology plc. 

### Taurus Park, Europa Boulevard, Warrington, WA5 5YT , United Kingdom Tel: +44 (0)1925 446139 Fax: +44 (0)192 5 446139 www.soundalert.com Fire Industry

Council Product Innovation Award



### Design Council Award

### I:\CIRC\MSC\1168.doc INTERNATIONAL MARITIME ORGANIZATION 4 ALBERT EMBANKMENT LONDON SE1 7SR

Telephone: 020 7587 3152 Fax: 020 7587 3210 

## IMO 

# E

Ref. T4/4.01 MSC/Circ.1168 1 June 2005

INTERIM GUIDELINES FOR THE TESTING, APPROVAL AND MAINTENANCE OF EVACUATION GUIDANCE SYSTEMS USED AS AN ALTERNATIVE TO LOW-LOCATION LIGHTING SYSTEMS

1 The Maritime Safety Committee, at its seve nty-fifth session (15 to 24 May 2002), recognized the need for the development of guidelines for th e testing, approval and maintenance of evacuation guidance systems used as an alternative to low-location lighting systems required by SOLAS chapter II-2 and the FSS Code.

2 The Committee, at its eightieth session (11 to 20 May 2005), having c onsidered a proposal by the forty-ninth session of the Sub-Committee on Fire Protection, approved the Interim Guidelines for the testing, approval and maintenance of evacuation guidance systems alterna tive to the low-location lighting systems, set out in the annex.

3 Member Governments are invited to apply the annexed Interim Guidelin es and submit to the Sub-Committee on Fire Protection information on e xperience gained in the implementation of the Interim Guidelines and on any progress made in the development of the testing, approval and maintenance of evacuation guidance systems.

4 Member Governments are also invited to br ing the annexed Interim Guidelines to the attention of ship designers, shipowners, ship opera tors, shipbuilders and other parties involved in the design, construction, testing, approval and maintenance of evacuation guidance systems.

***

## MSC/Circ.1168

I:\CIRC\MSC\1168.doc 

## ANNEX

INTERIM GUIDELINES FOR THE TESTING, APPROVAL AND MAINTENANCE OF EVACUATION GUIDANCE SYSTEMS USED AS AN ALTERNATIVE TO LOW-LOCATION LIGHTING SYSTEMS

1 Scope

The purpose of these Guidelines is to provide st andards for the testing, approval and maintenance for alternative systems to low-location lighti ng systems required by SOLAS regulation II-2/13.3.2.5.1 and chapter 11 of the FSS Code.

2 Testing

2.1 Test for corridors should be performed in redu ced visibility using theatrical (white) smoke with an Optical Density at least OD 0.5 m -1 ∗ 

## . Measuring equipment shoul d conform to a standard acceptable to the Administration.

2.2 If the system is to be installed in public spaces, the test should be performed in reduced visibility using theatrical (white) smoke with an Optical Density at least OD 0.1 m -1



## . 2.3 Test for stairway enclosures should be performed in clear (no smoke) conditions.

2.4 A minimum 80% of the participants should r each the pre-designated exit with a speed of movement of at least 0.7 m/s calculated using th e distance measurement of the optimum route. Participants achieving a speed of movement of le ss than 0.7 m/s should be deemed to have failed. There is no speed of movement criterion applied to stairway enclosure tests.

2.5 The maximum percentage of participants choosing failed exits should not exceed the value of 2% for public spaces and 5% for accommodation areas, corridors and stairway enclosures.

2.6 In the public space configuration when testing with two correct exits, no more than 15% of the participants may choose the more distant exit.

2.7 There should be a minimum of 60 participants for each test - being at least 8 and not more than 12 of each age group 16-25, 26-35, 36-45, 46-55, 56-65, 66-75 with an average of 45-55% male/female of the entire group.

2.8 A ìcontrolî test should be performed with no guidance system in operation in order to demonstrate that there is no significant inherent bias to favour the pre-designated exit. Participants of the ìcontrolî test should not participate in any previous or subsequent tests.

2.9 For the purpose of this section:

.1 a ìcorrect exitî is an exit to which th e evacuation guidance system intentionally guides participants;

∗ 

### Refer to the United Kingdom Governmentís Health and Safety Executive (HSE) 1998 report: OTH 533 Emergency Way Guidance Lighting Systems ( http://www.hse.gov.uk/research/othpdf/500-599/oth533.pdf ).

## MSC/Circ.1168 ANNEX Page 2

I:\CIRC\MSC\1168.doc 

## .2 participants arriving at any of the ìfail exits î are deemed to have ìfailedî the test and should be stopped at that point;

.3 only one participant should be in the test at a time in order to preclude any crowd behavioural influence;

.4 the test area should be illuminated by the emergency lighting as required by SOLAS; and

.5 during the test signage other than those be ing part of the test should not be used.

3 Test facility design

3.1 Public spaces

3.1.1 If the system is intended to be installed in public spaces, the test facility should be designed so that participants are required to navigate to a pre-designated exit across a public space, where the shortest distance to that exit is not along a wall. A minimum of two exits should be provided to test the ability of participants to identify and proceed to an exit within an open space. An additional fail exit should be located 2 to 3 m from each correct exit.

3.1.2 The test room should be not less than 15 m by 10 m with the start point and pre-designated exit being on the long sides, diagonally opposite each other, such that the distance around the walls is approximately equal in either direction. Th e density of the smoke should be great enough to prevent a participant from being able to see no more than half to two-thirds of the distance to the nearest exit OD 0.1 m -1 

## . Direct distance between start and a correct exit should be not less than 12 m.

3.2 Accommodation areas and corridors

The test layout should be such that participants should be required to navigate correctly their way to a pre-designated exit via at least four decision points including at least two cross-junctions and at least one T-junction

. It should not be possible to navigate the correct route by re maining attached to one continuous wall. The correct route should in clude the placement of a non-exit door within 2 to 3 m of the correct exit door. A non-exit door is a fail exit. The total distance travelled over the correct route should be not less than 25 m, with the distance between decision points being not less than 5 m.

3.3 Stairway enclosures

Participants should be required to use the stairw ay enclosures to a pre-designated floor. The participants should enter the stairway enclosures from a mid-point where each will be instructed by the guidance system to proceed either up or dow n. The option of up or down should be randomly chosen.

4 Participant briefing

Participants to be briefed on the purpose of the test and the technology to be tested, using the proposed briefing technique that would be used in the implementation on board ship, e.g. the briefing

## MSC/Circ.1168 ANNEX

Page 3

I:\CIRC\MSC\1168.doc 

## given during lifeboat drill, instructions on backs of cabin doors or via the shipís public address system, etc. No briefing should be given on the route, test layout or numbers of exits.

5 Approval

All systems should be approved by the Administ ration for compliance with the Performance standards for evacuation guidance systems (MSC/C irc.1167) developed by th e Organization and, for electrically powered systems, IEC 60092 Electrical Installations in Ships. Installation requirements should be included in the approval procedures , and individual onboard arrangements should be verified accordingly.

6 Maintenance

6.1 All elements of the system should be visually examined and checked at least once per week, and a record thereof should be kept. All mi ssing, damaged or inoperable elements should be replaced.

6.2 All systems should have their signal tested at least once every five years. Readings should be taken on site. Should any reading be found to be outside manufacturerís tolerances, then that element of the system should be replaced.

__________

# News Update

American Bureau of Shipping June 2002 Vol.11, No.3



# Maritime Safety Committee’s

75 th 

# Session

15 to 24 May 2002

Refer also: www.eagle.org / News and Events / Regulatory Information

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3)



### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.orgMSC – 75 th Session (15 - 24 May 2002)

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3) page 1 /11 

### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.orgMSC – 75 th Session (15 - 24 May 2002)

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3) page 2 /11 

### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.org



# International Regulation News Update June 2002 Refer also: www.eagle.org / News and Events / Regulatory Information Regulatory Development Ship + 

## Application


# OPENING REMARKS (page 2) 

# MARITIME SECURITY (pages 2 & 3) 

## All Ships Ship Security Plans Security Alarm Automated Identification Systems (AIS) IMO Number Continuous Synopsis Record (CSR) Container Security 

# SOLAS AMENDMENTS AND INTERPRETATIONS (pages 3 & 4) 

## Enhanced Surveys Oil Tankers and Bulkers IMDG Code All Ship s Ships Under Construction on 1 July 2002 All Ships 

# PERMANENT ACCESS (pages 4 - 6) 

## Oil Tankers and Bulkers Draft SOLAS Regulation Ship Structures Access Manual Draft Technical Provisions – Bulk Carriers Draft Technical Provisions – Oil Tankers 

# BULK CARRIER SAFETY (pages 6 & 7) 

## Bulk Carriers Water Ingress Monitoring/Alarm Dewatering Systems Hatch Cover Design Loads 

# MISCELLANEOUS (pages 7 - 10) 

## Safety of Large Passenger Ships Passenger Ships Passenger Ship Evacuation Analysis Passenger Ship s STCW Transitional Period to End All Ships Cargo Securing Strength All Ships Asbestos Monitoring Guidelines All Ships Testing of Watertight Doors All Ships Thermal Protection Assessment All Ships Immersion and Anti-exposure Suits All Ships ISM Majo r Non-Conformities All Ships Emergency Towing Arrangements Existing Oil Tankers HSC Model Test Guidelines High Speed Craft 

# FIRE SAFETY (pages 10 & 11) 

## All Ships FTP Code Type Approval Smoke Detectors Smoke Control
( + “ships” are all self propelled vessels)MSC – 75 th Session (15 - 24 May 2002)

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3) page 3 /11 

### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.org 

### OPENING REMARKS
The 75th session of the Maritime Safety Committee (MSC) met from 15 to 24 May 2002 at IMO Headquarters in London. Secretary General William A. O’Neil highlighted a number of ongoing efforts but focused on this session’s most prominent agenda item -- the progress made by an intersessional working group, funded by the United States of America, to develop regulation aimed at improving maritime security.

A number of amendments to the SOLAS Convention were adopted together with MSC Circulars containing recommended guidelines supplementing SOLAS regulations.

MARITIME SECURITY
Work continued on the development of a revised SOLAS Chapter XI to include maritime security regulations in addition to maritime safety. A second intersessional working group funded again by the USA is scheduled for 9-13 September so that a final draft of the revised Chapter XI and a new Maritime Security Code can be completed for adoption at the December 2002 Diplomatic Conference. Draft requirements approved at MSC 75 include the following provisions, which will be subject to survey and periodic certification by a special agency of the Administration or on behalf of the Administration by a recognized organization with special security expertise.

Ship Security Plans Passenger ships, cargo ships > 500 gt and mobile offshore drilling units must be provided with a ship security plan. The plan should contain procedures and measures to prevent introduction of weapons; identify shipboard restricted areas; provide procedures for responding to security threats and evacuation; assign shipboard security duties including auditing, training and drill procedures. It is possible that the ship’s Security Plan may be combined with the ISM Safety Management System. New positions ashore and onboard by a designated ship and Company Security Officer will be required and responsible for implementing these plans. Records are to be maintained to document the plan’s effective implementation.

Security Alarm Every cargo ship > 500 gt, passenger ship and drilling unit constructed on/after 1 July 2004 will be required to be fitted with a ship security alarm which shall automatically alert shore authorities that the ship’s security is under threat or is being compromised. The alert shall continue until it is deactivated by an authorized personnel. The alert shall not be sent to other ships and shall not raise an alarm on board. Existing passenger ships, tankers, bulk carriers and high speed craft will need to be retrofitted with such alarms by the first radio installation survey after 1 July 2004. All other cargo ships

> 500 gt and drilling units need to comply by the first radio installation survey after 1 July 2006.

Automated Identification System (AIS) Agreement could not be reached on one of the four proposals tabled on accelerating the implementation dates for retrofitting AIS to ships (other than passenger ships and tankers) between 300 and 50,000 gt. The current range varies from 2004 to 2007 according to cargo ship size. The proposals range from 1 July 2004 (USA) to 2006 (Russia) with the European Union proposing a middle range beginning 1 July 2004 with full implementation by 1 July 2005.

IMO Number The ship’s assigned IMO Number is to be marked externally on the ship’s stern, the front of the superstructure or on both sides of the ship by the plimsol mark. It is also to be marked internally on a bulkhead of a machinery space, a pump room (for tankers), or a ro-ro space (for roro ships) or on a hatchway (for bulk carriers). This applies to passenger ships > 100gt and cargo ships > 300 gt built on/after the expected entry into force date (1 January 2004) and to existing ships at the date of the first dry docking due thereafter.

Continuous Synopsis Record (CSR) All passenger ships > 100gt and cargo ships

> 300 gt are to be provided with a CSR which indicates the ship’s history from the date on which this regulation is scheduled to enter into force (1 January 2004). The Administration is toMSC – 75 th Session (15 - 24 May 2002)

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3) page 4 /11 

### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.org 

### issue the CSR which shall at least contain the history of the ship’s name, registered bareboat charterer, Flag, class society, ISM (DOC and SMC) issuer and registered owner.

Container Security The shipper shall ensure the security of a loaded container before it is offered for shipment on board. Two alternative means to ensure security are under consideration:

• Electronic Seal – records the seal’s unique identification number for the container’s number to which it is affixed and the status of the seal based on ISO Standard 18185,

“ Freight Containers - Radio Frequency Communication Protocol for Electronic Seal ”; and

• Mechanical Seal – a high security seal that is uniquely numbered. Reference has been made to ASTM Standard F832,

“ Classification of Security Seals, Level D”

.

SOLAS AMENDMENTS AND INTERPRETATIONS

Enhanced Surveys Resolution A.744(18) on enhanced surveys was amended to bring it in line with IACS Unified Requirements that are already implemented by IACS Member Societies. The amendments are contained in resolution MSC.125(75) and include the following provisions which enter into force on 1 January 2004: Prompt and Thorough Repair on oil tankers and bulk carriers is to be carried out at the time of survey, except if adequate repair facilities are not available. The repair is to be permanent so as to alleviate the need to record it as a condition of classification to be followed up at the next survey.

Thickness Measurements of corrugated transverse bulkheads between the first two cargo holds in bulk carriers are contained in a new Annex. In order to assess their strength to resist the flooding of the No.1 cargo hold each vertical corrugation, corrugation flange, web shedder plate and gusset plate at two transverse bands is to be measured. This applies to existing single side skin bulk carriers (of 150 m length or above, carrying solid bulk cargoes having a density > 1.78 tons/m 3 

### , constructed before 1 July 1999. Additionally, thickness measurements carried out at any of the required surveys, if not carried out by the class society itself, must be witnessed by a surveyor to the extent necessary to control the measurement process to assure that the measurements represent the actual average condition of the structural member. Annual Survey Requirements for the foremost cargo hold of existing bulk carriers described above which do not have a sufficient number of cargo holds to meet the damage stability requirements of SOLAS regulation XII/9.1. For bulk carriers between 5-15 years of age a minimum of 25% of the frames are to undergo close-up survey. This increases to 100% at ages exceeding 15 years. Accelerated Implementation of survey requirements for bulk carriers and tankers more than 15 years of age require the intermediate survey to be the same extent as the prior special survey, except for pressure testing of cargo holds and tanks unless otherwise considered necessary by the surveyor. An overall survey of every ballast tank is to be carried out for bulk carriers at > 10 years of age and tankers > 5 years of age at their intermediate survey. Further, close-up surveys of ballast and cargo tanks are to be to the same extent as the previous periodical survey for tankers > 10 years of age. Previously, these intermediate survey requirements were not specified for bulk carriers and were required for tankers more than 10 yrs of age. Also, ballast tanks sharing a common plane with a heated cargo tank must be internally examined on an annual basis for tankers exceeding 15 years of age.

IMDG Code Resolution MSC.123(75) contains amendments to SOLAS Chapter VII that will, when it enters into force on 1 January 2004, require packaged goods and goods carried in bulk to comply with the International Maritime Dangerous Goods (IMDG) Code. This applies to all cargo ships regardless of size and to ships carrying more than 12 passengers. However, not all of the provisions of the Code have been made mandatory and the following provisions remain voluntary:MSC – 75 th Session (15 - 24 May 2002)

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3) page 5 /11 

### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.org 

### • Training of officers and ratings responsible for cargo handling on ships and shore-based personnel;

• Transport of explosives relative to hazard division, compatibility and classification;

• The determination of flash point (a measure of risk of formation of explosive or ignitable mixtures when the liquid escapes from its packing);

• Column 15 of the Dangerous Goods List - the emergency schedule ( EmS) number to identify when the "Emergency Procedures for Ships Carrying Dangerous Goods" is to be provided by the shipper;

• Column 17 of the Dangerous Goods List - properties and observations of goods;

• The transport schedules for class 7 Radioactive Material;

• Multi-modal Dangerous Goods Form

• Special provisions in the event of an incident and fire precautions.

Ships Under Construction on 1 July 2002 The MSC agreed that the term first survey includes the initial survey in addition to the annual and periodical surveys when applying the retroactive requirements calling for the fitting of the following equipment at the first survey on/after 1 July 2002 (or 2003 for AIS):

• Global Positioning System (GPS)

• Automated Identification System (AIS);

• Voyage Data Recorder (VDR) for passenger ro-ro ships. Under SOLAS, the Initial Survey includes all the survey work necessary to issue a certificate before the ship is put in service. Therefore, a ship built before 1 July 2002 which is put in service and issued a valid safety equipment or passenger safety certificate on/after 1 July 2002 (or 2003 for AIS) needs to comply with the regulations referenced above when it is put into service. Conversely, a ship which is put in service and issued certificates before 1 July 2002 (or 2003 for AIS) has until the date of the first annual or the first renewal survey for safety equipment/passenger safety, whichever occurs first after 1 July 2002, (or 2003 for regulation V/19.2.4) to comply. PERMANENT ACCESS

Draft SOLAS Regulation A draft SOLAS regulation applicable to oil tankers > 500 gt and bulk carriers > 20,000 gt, constructed on or after 1 January 2005 was presented to the MSC for approval. The MSC decided to delay final review and adoption until MSC 76 (December 2002). The draft regulation calls for each space within the cargo area to be provided with a permanent means of access to enable, throughout the life of a ship, overall and close-up inspections and thickness measurements of the ship’s structures to be carried out by the Administration, the Company, as defined in regulation IX/1, and the ship’s personnel. The means of access is to comply with the requirements of regulation II-1/12-2 and with a mandatory set of Technical Provisions

. Where a permanent means of access may be susceptible to damage during normal cargo loading and unloading operations or where it is impracticable, the Administration may allow, in lieu, the provision of portable means of access such as staging, moveable platforms and ladders as specified in the Technical Provisions

, provided the means of attaching, rigging, suspending or supporting the portable means of access forms a permanent part of the ship’s structure. All portable equipment shall be capable of being readily erected or deployed by ship’s personnel. The means of access shall be subject to survey prior to, or in conjunction with, its use in carrying out surveys in accordance with regulation XI/2. Safe access to cargo holds, cofferdams, ballast tanks, cargo tanks and other spaces in the cargo area shall be direct from the open deck and such as to ensure their complete inspection. Access to double bottom spaces may be from a pump-room, deep cofferdam, pipe tunnel, cargo hold, double hull space or similar compartment not intended for the carriage of oil or hazardous cargoes. Tanks, and subdivisions of tanks, having a length of 35 m or more shall be fitted with at least two access hatchways and ladders, as far apart as practicable. Tanks less than 35 m in length shall be served by at least one access hatchway and ladder. When a tank is subdivided by one or more swash bulkheads orMSC – 75 th Session (15 - 24 May 2002)

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3) page 6 /11 

### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.org 

### similar obstructions which do not allow ready means of access to the other parts of the tank, at least two hatchways and ladders shall be fitted. Each cargo hold should be provided with at least two means of access as far apart as practicable. In general, these accesses should be arranged diagonally, e.g

. one access near the forward bulkhead on the port side, the other one near the aft bulkhead on the starboard side. Horizontal openings , hatches or manholes shallbe sized to allow a person wearing a selfcontained air-breathing apparatus and protective equipment to ascend or descend any ladder without obstruction and also provide a clear opening to facilitate the hoisting of an injured person from the bottom of an internal space. The minimum clear opening shall not be less than 600 mm 

### x 600 mm 

### . When access to a cargo hold is arranged through the cargo hatch, the top of the ladder shall be placed as close as possible to the hatch coaming. Access hatch coamings having a height greater than 900 mm 

### shall also have steps on the outside. Vertical openings , or manholes, in swash bulkheads, floors, girders and web frames providing passage through the length and breadth of the space, shall have a minimum opening not less than 600 mm 

### x 800 mm 

### at a height of not more than 600 mm 

### from the bottom shell plating unless gratings or other foot holds are provided.

Ship Structure Access Manual A ship’s means of access to carry out “ close-up” inspections and thickness measurements shall be described in a Ship Structure Access Manual approved by the Administration, an updated copy of which shall be kept on board. The Ship Structure Access Manual shall include the following for each space in the cargo area:

• plans showing the means of access within each space, with appropriate technical specifications and dimensions, to enable close-up inspections to be carried out;

• instructions for inspecting and maintaining the structural strength of all means of access and means of attachment, taking into account any corrosive atmosphere that may be within the space; • instructions for rigging and use of portable equipment; and

• an inventory of all portable means of access with safety instructions for the rigging.

Draft Technical Provisions – Bulk Carriers Cargo Holds ( Vertical Structure) - Permanent vertical access to allow for inspection of a minimum of 25% of the total number of hold frames port and starboard equally distributed throughout the hold including at each end in way of transverse bulkheads. In no case should this arrangement be less than three permanent means of vertical access. Means to readily secure safety cages to the permanent means of access are to be provided. A means of portable access may be used to gain access over the sloping plating of lower hopper ballast tanks to the lower brackets.

Cargo Holds ( Overhead Structure) - Three permanent means of access shall be fitted at both ends of sides of the cross deck and in the vicinity of the centerline. Each access is to be accessible from the cargo hold or directly from the main deck and is to be installed between 1.8 m 

### to 2.5 m 

### below the deck. Alternatively, if the height of the overhead structure of the cross deck is less than 17 m 

### , a movable means of access (e.g., hydraulic arms with a stable base or wire lift platforms) may be accepted.

Lower Hopper Tanks – T anks ≥ 5m in height are to be provided with one longitudinal, continuous permanent means of access for the full length of each tank, adjacent to side shell at 1.8 m 

### to 2.5 m 

### below the deck with vertical access ladders to the main deck access. Access holes are to be arranged at each transverse ring web within 600 mm 

### of the tank base. Where the bottom web frame rings have a web height greater than 1m, step rungs/grab rails are to be provided to allow safe access over each transverse web frame ring and bottom web frame rings. Portable ladders may be used for a tank height < 5 m 

### . Top Side Tanks - T

anks ≥ 5m in height are to be provided with one longitudinal, continuous permanent means of access is to be provided for the full length of each tank, adjacent to side shell at 1.8 m



### to 2.5 m 

### below the deck with vertical access ladders to the main deck access. Three (3) permanent vertical ladders are to be providedMSC – 75 th Session (15 - 24 May 2002)

ABS REGULATORY AFFAIRS : INTERNATIONAL REGULATION NEWS UPDATE , J UNE 2002 ( V OL 11, N O .3) page 7 /11 

### For further information, contact ABS Regulatory Affairs at tel 201-226-5320 | fax 201-226-5314 | email: gshark@eagle.org 

### from bottom shell to the top of the lower hopper plating at side shell connection fitted at each end and mid-span. Access holes are to be arranged at each transverse ring web within 600 mm 

### of the tank base. Where the bottom web frame rings have a web height greater than 1m, step rungs/grab rails are to be provided to allow safe access over each transverse web frame ring and bottom web frame rings. Portable ladders may be used for a tank height < 5 m 

### .

Draft Technical Provisions – Oil Tankers Cargo & Inboard Ballast Tanks

Overhead Structure

- is to be provided with one

c ontinuous athwartship permanent access arranged at every deck transverse on the clean (unobstructed) side of the web plating from 1.8 m 

### to 2.5 m 

### below the deck. Lightening holes (300 m m 

### φ ) shall be cut in the web plating, (each side of and adjacent to) each tripping bracket at a minimum of 3 locations. The athwartship

accesses are to be accessible from a continuous longitudinal permanent access provided at the longitudinal bulkhead

. Where a longitudinal bulkhead contains attached framing, the access shall be provided on that side. Portable ladders may be used for a tank height < 5 m 

### . Vertical Structure

- is to be provided with p ermanent access unless the tank height is less than 5m in which case portable ladders may be an acceptable alternative. Wing Ballast Tanks > 5m width

Overhead Structure

- is to be provided with one

c ontinuous longitudinal permanent access provided for the full length of the tank from 1.8 m 

### to 2.5 m 

### below the deck with means to pass through swash bulkheads. Vertical access ladders are to be provided at each end of the tank and at its mid-span. Portable ladders may be used for a tank height < 5 m 

### . Vertical Structure

- is to be provided with permanent access to each transverse web between horizontal stringers from the upper knuckle point of the bilge hopper section to the main deck. If the distance between these members < 5 m 

### , portable ladders may be used BULK CARRIER SAFETY

Water Ingress Monitoring/Alarm

IMO’s first action taken relative to the UK’s second formal inquiry into the loss of Derbyshire is contained in a set of new requirements for water ingress alarms. Single and double side skin bulk carriers > 500 gt built on/after 1 July 2004 (when they are put in service) and existing bulk carriers (by the first intermediate or renewal survey carried out thereafter) will need to be provided with water level alarms giving audible and visual indication on the navigation bridge when water is detected:

• at 0.5m and 15% cargo hold depth (but not more than 2m) shall be fitted at the aft end of each cargo hold. Bulk carriers which do not meet the damage stability requirements of SOLAS regulation XII/9.2 need only be provided with the higher level alarm;

• at a level corresponding to 10% capacity of any ballast tank forward of the collision bulkhead; and

• at 0.1m above the deck of any dry or void space (other than a chain locker) which extends forward of the foremost cargo hold. There was some support for the U.K. proposal to accelerate the implementation schedule for existing bulk carriers from the first intermediate or renewal survey carried out after 1 July 2004 to the first annual survey carried out thereafter. BIMCO has reported that they may submit a paper to MSC 76, which is scheduled to adopt this regulation, arguing against such a proposal recognizing that the fitting of these alarms, particularly in cargo holds, will require flame cutting, welding, staging, cabling, etc., which is more safely carried out when the ship is in dry dock as opposed to the use of riding crews during operation. IACS has adopted Unified Requirement S24 which contains a different implementation schedule as well as system requirements. UR S24 calls for single side skin bulk carriers > 500 gt built on/after 1 January 2003 (when they are put in service) and existing bulk carriers (by the first intermediate or renewal survey carried out thereafter if > 10 years of age on 1 January 2003 or by 10 years of age if <10 years of age on 1 January 2003) will need to be provided with water level alarms giving audible and visual indicationMSC – 75 th Session (15 - 24 May 2002)

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### on the navigation bridge when water is detected at 2 m 

### above the cargo hold bottom.

Dewatering Systems Subject to adoption by MSC 76 in December 2002, bulk carriers > 500 gt built on/after 1 July 2004 (when they are put in service) and existing bulk carriers (by the first intermediate or renewal survey carried out thereafter) will need to be fitted with a means of dewatering ballast tanks and dry spaces, any part of which extends forward of the collision bulkhead. Means of operation shall be readily accessible from an enclosed space that is accessible from the navigation bridge or propulsion control position without having to traverse exposed decks.

Hatch Cover Design Loads Based on the UK’s presentation of results of model tests carried out in association with the the MV Derbyshire casualty at LancasterUniversity, the MSC tasked the SLF SubCommittee to update the design loads for hatch covers contained in the 1966 Load Line Convention taking into account the above model test results.
These tests were carried out in head, bowquartering and beam seas on one Panamax (83k displacement) and two Capesize (188k and 204k displacement) bulk carriers. Vertical, transverse and horizontal loads on the hatches were measured on deck from mid-length forward, for three speeds (0, 13.5 and 15.5 knots). The tests did not indicate any clear trends as to the influence of speed on the vertical loads as there were inconsistent readings across the range of test conditions. The Model Test Report places emphasis on the predicted longitudinal loads as they were well above the limiting loads of hatch covers to avoid longitudinal displacement -- reported to be 45kPa by industry sources. In light of this, the UK expressed concern that IACS Unified Requirement S21, which provides for a more robust hatch cover than the 1966 Load Line Convention, may also need to be revised. IACS UR S21 requires net thickness (after a corrosion margin is deducted) to be used and takes into account design speed, coaming height above water, hull form and the hatch cover’s longitudinal location. Preliminary results of IACS current assessment of UR S21 that become available will be presented to the SLF Sub-Committee during its upcoming 45 th 

### Session (22-26 July 2002). IMO discussions are currently focused on new bulk carriers, although IMO noted IACS’ announcement to implement an equivalent requirement to existing bulk carriers and plans to wait for this outcome.

FSA Studies The MSC considered progress reports from studies not yet completed (UK/International FSA Collaboration) and final reports from completed studies (by Norway/ICFTU, Japan and IACS) in developing a list of preliminary risk control options ( RCO’s).

The MSC was conscious of the fact that the list is tentative pending receipt of final FSA study reports, that some of the RCO’s take into account the enhanced survey amendments to A.744(18) presented above, and that further study is needed to evaluate applying an RCO in conjunction with others or individually. The approved list of tentative RCO’s address:

• Improved structural robustness, reserve buoyancy ( focsle/bulwark), and corrosion control & protection of the hull envelope;

• Improved robustness of hatch covers, deck fittings and their closing mechanisms;

• Enhanced evacuation warnings and abandonment provisions;

• Operational enhancements including increased control of loading capabilities and weather routing; and

• Earlier implementation of the structural survivability provisions of SOLAS Chapter XII (which IACS has accelerated from 15 to 10 years of age with effect from 1 January 2003). IACS has announced the following five measures are under development with a target to complete the requirements in time to give owners sufficient notice to plan for and implement the modifications by the due date of the next Intermediate or Special Survey commenced on or after January 1, 2003:

• Installation of improved bulwark or breakwater structure on existing bulkMSC – 75 th Session (15 - 24 May 2002)

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### carriers when not fitted with a forecastle, and a forecastle on new vessels to providemore protection for forward hatches and foredeck fittings;

• Increased integrity of fore-deck fittings on existing and new bulk carriers to resist green water loading;

• Implement hatch cover requirements to the forward 25% length of existing vessels that are generally equivalent to UR S21 requirements for new vessels;

• Implement requirements for the strength of side shell frames to existing vessels taking into consideration IACS UR S12, which currently is applicable to new bulk carriers; and

• Fit water ingress detection and alarms for spaces forward of the cargo area.

MISCELLANEOUS

Safety of Large Passenger Ships Continuing its effort to undertake a global, holistic evaluation of potential risks associated with large passenger ships, the MSC further refined its objectives and assigned a number of specific task to its Sub-Committees. Based on the guiding philosophy that places emphasis on casualty prevention, improving survivability of the ship as a safe haven for its passengers, twelve tasks were assigned to relevant Sub-Committees, the last three of which were retained by the MSC: 1) Improve ship survivability against grounding, collision or flooding; 2) Assess fire protection and prevention measures (active/passive); 3) Assess emergency evacuation considering ship survival time and crowd management in light of any new technologies; 4) Review LSA functional requirements to develop performance-based standards; 5) Evaluate recovery and rescue techniques considering capacity of SAR services to rescue large numbers of passengers; 6) Develop measures to assess alternative designs to facilitate use of new technologies; 7) Review ship operations and management considering safe manning levels, communication issues and officer/crew training levels; 8) Assess safety to proceed to port after fire/flooding by identifying essential systems and considering redundancy provisions; 9) Review hardware and human element measures to prevent grounding; 10) Review medical management practices, equipment, qualifications and staff levels; 11) Improve ship security (underway by MSC); 12) Review measures including food handling and sanitation relative to health-safety. One new technology that is currently being considered under Task 3 is a proposal by the U.K. to allow the use of directional sound as an alternative to low location lighting for evacuation. Placed at discrete locations, trial testing shows much improved evacuation times in smoke-filled spaces as the emitting sound was clearly identified and distinguishable against sound levels of a fire and one’s own breathing apparatus. Costs have been estimated to be 20% lower than low location lighting. There had been a proposal to quantify (at least nominally) the size of passenger ships (e.g., length, tonnage, number of persons) under consideration by this task. However, the MSC decided that it would be more appropriate for the individual Sub Committees to consider size as it may vary according to the assigned task.

Passenger Ship Evacuation Analysis To facilitate prompt evacuation by passengers and crew along escape routes, taking into account possible congestion that may occur due to crew movement in an opposite direction and the possibility that certain escape routes, assembly stations, embarkation stations or survival craft may be unavailable as a result of a casualty, the Committee approved MSC/Circ.1033 which contains interim guidelines to assess the adequacy and flexibility of escape arrangements.

Evacuation time limits are recommended to not exceed 60 min



### for ro-ro passenger ships and passenger ships with no more than three main vertical zones and 80 min 

### for all other passenger ships. Evacuation time, calculated by a simplified method or by simulation analysis, is defined as the total time it takes all persons to travel (calculated in a probabilistic manner) toMSC – 75 th Session (15 - 24 May 2002)

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### their assigned assembly station plus 2/3 of the time it takes to embark and launch life boats (30 min 

### .maximum). Scenarios are assessed for evacuation during day and night, with different initial distribution of passengers and crew throughout the ship.

STCW Transitional Period to End

The MSC recalled that IMO’s approved extension of the 1 February 2002 transitional period deadline will expire on 31 July 2002. TheMSC also noted that after 31 July, major nonconformities could be raised against a ship and the Company in cases where the seafarer did not hold the necessary STCW 95-compliant certificates or endorsements. In this regard, Japan informed the Committee that a concentrated campaign recently undertaken by the Paris MOU had indicated that approximately 35% of ships inspected had deficiencies in seafarers’ certification.

Cargo Securing Strength The Committee approved MSC/Circ.1026 which revises the advanced calculation method to determine the strength of securing equipment/lashings contained in the Cargo Securing Code. The new Circular:

• Revises the existing safety factor (1.5) used to determine the calculated strength of the device based on the device’s safe working load (i.e., CS = SWL/1.5). For all calculations of force and moment a safety factor of 1.5 is to be used, except for tipping where 1.35 is to be applied;

• Provides for a more uniform definition of the horizontal securing angle given that securing devices do not usually have a pure longitudinal or transverse direction in the horizontal plane; and, based on this more uniform definition,

• Provides expanded tables of force coefficients as a function of friction and horizontal securing angles.

Asbestos Monitoring Guidelines The MSC approved MSC/Circ.1045 which sets out guidelines for setting up a maintenance and monitoring program with the principal objective of minimizing exposure of all crew and passengers on board to asbestos fibers while the ship is “ in service ” as opposed to when the ship is in a repair or dry dock. The guidelines consider three scenarios where there may be general exposure, where more direct exposure in working areas with a reasonable likelihood of asbestos/fibers and where asbestos/fibers are present (except for the three applications in pumps, fire risk watertight joints and high temperature flexible couplings permitted by SOLAS). An inspection and assessment on board ship by qualified professionals is also recommended.

Testing of Watertight Doors The MSC approved an alternative means to test the watertightness of doors fitted in passenger ships and cargo ships where testing may cause possible damage to insulation or outfitting items. As an alternative to testing by water pressure to a head up to the bulkhead or freeboard deck respectively, prototype pressure testing (before the door is fitted) of each type and size of door with a test pressure corresponding at least to the head required for the intended location may be accepted. Installation and fit-up shall correspond to that of the prototype test with each door checked for proper seating. This regulation II-1/18 is scheduled for adoption at MSC 79 in December 2004.

Thermal Protection Assessment The MSC approved MSC/Circ.1046 which provides information to assist in assessing the impact of environmental factors, specifically water temperature on thermal protection equipment selection in the context of hypothermia. Based on the criteria that thermal protective performance for various types of equipment is defined as the time to reach a deep body temperature of 35 0 

### C or reduce a deep body temperature by 2 0 

### C, where a significant degree of incapacitation is expected to occur, the Guidelines provide for comparison purposes only the following table of relative performance characteristics for equipment.ThermalProtectiveMeansLifejacketThermalProtectiveLifejacketAnti-ExposuresuitImmersionsuit(UnImmersionsuit(Insulated)



### IMO Minimum Test RequirementsMSC – 75 th Session (15 - 24 May 2002)

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### Time na 2h 1h 1h 1h
Temp

- 10 0 

### C 5 0 

### C 5 0 

### C 2 0 

### C Time for core temp drop of 2 0 

### C or to 35 0 

### C When exposed to water with temps at left
0 0 

### C

- 0.5h 1.5h 1.5h 6h

5 0 

### C 0.5 h 0.75h 2h 2h >12h

10 0 

### C 0.8h 2h 4h 5h >12h

20 0 

### C 1.7h 2h 10h >12h >12h

Immersion and Anti-exposure Suits The MSC approved MSC/Circ.1047 which provides guidance to the crew, when inspecting immersion suits and anti-exposure suits required by SOLAS, to check the storage bag’s general condition and that closures remain satisfactory for ease of suit removal. The suit, which should be dry inside and out and free of deterioration, should correspond to the type and size identified on the bag. Donning instructions should be legible and zippers should easily operate. Inflatable head support and/or buoyancy ring where fitted should be checked monthly for damage and inflated quarterly.

ISM Major Non-Conformities Upon MEPC’s October 2002 anticipated concurrence with MSC’s approval, additional ISM guidelines will be issued for certifying compliance with the ISM Code. The revision embraces the IACS practice of allowing a major non-conformity to be downgraded, provided a corrective action plan is presented to the auditor prior to completion of the audit. Such a practice is carried out in lieu of withdrawing the ISM certificate which, in the case of a withdrawn DOC, automatically invalidates the associated SMC’s. Somewhat different than the current guidelines (which require an audit equivalent in scope to that of an initial audit in order to revalidate thewithdrawn certificate) a downgraded major nonconformity can be accepted provided an additional audit is satisfactorily completed within a time period not to exceed 3 months. During this period a short term certificate is issued to allow for the accumulation of objective evidence demonstrating the effective functioning of the SMS with respect to the corrective action implemented relative to the major nonconformity.

Emergency Towing Arrangements The Committee approved resolution MSC.132(75) which clarifies that the emergency towing arrangements fitted on existing tankers in accordance with resolution A.535(13) may be retained provided that the towing arrangements at one end of the ship are pre-rigged for ready deployment as per the requirements of the current Guidelines contained in resolution MSC.35(63).

HSC Model Test Guidelines The Committee approved MSC/Circ.1029 which contains guidelines for the conduct of model tests for Ro-Ro High Speed Craft (HSC) in the event that such tests are to be used as a basis for exemption from the requirement to fit an inner bow door under the 2000 HSC Code.

The intent of the tests is to demonstrate that the craft satifies certain residual stability criteria with accumulated water on the vehicle deck(s) as a result of failure of the bow shell door. Tests are required to be carried out for several headings and durations (which may be successively accumulated to represent the recommended 10 minutes of full scale operation). The accumulated water may be determined by direct measurement at the end of each test or by calculation from measured relative water level within the vehicle space.

Tests should be carried out in waves with not less than two significant heights corresponding to 100% and 70% of the worst intended operating conditions using three narrow band JONSWAP spectra.

FIRE SAFETY
The MSC approved a number of circulars which contain recommendations and guidance relative to the application of fire safety regulations contained in SOLAS and the Fire Test Procedures (FTP) Code as summarized below.

FTP Code Type Approval The MSC approved MSC/Circ.1036 which recommends that type approval certificates forMSC – 75 th Session (15 - 24 May 2002)

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### windows should indicate which side of the window was exposed to the heating condition during the test and cite which of the optional tests was applied. The Circular recommends that the minimum window size tested under resolution A.754(18) be revised to reflect the maximum size and that the type of glass pane, its minimum thickness and gaps, if appropriate, should be commensurate for which approval is sought. Test results obtained on this configuration should, by analogy, allow for extending approvals to windows of the same type, but with lesser dimensions or greater thickness.

Smoke Detectors The MSC approved MSC/Circ.1035 which recommends that detectors fitted as equivalent to smoke detectors required by SOLAS should comply with Chapter 9 of the Fire Safety Systems Code. This includes requirements for power supply, performance, location and signal characteristics. The only exception is where carbon monoxide detectors are used, in which case the alarm threshold should be set at 40 ppm 

### with the ability of the detector to be adjusted to high and low sensitivity settings in order to obtain the optimum performance and to minimize false alarms

Smoke Control The MSC approved MSC/Circ.1034 sets out guidelines to prevent the entry of smoke from surrounding spaces into internal assembly stations in order to permit the assembling of passengers. For atriums , smoke control and ventilation systems should be capable of maintaining visibility in atriums in order to assist in safe escape and to allow fire-fighters to operate. Compliance with the above performance standard is facilitated by requiring each internal assembly station and atrium to be served by a separate ventilation system that is independent of systems serving other spaces. Relative to the normal pressure found in surrounding spaces, the system is to maintain a negative pressure for the atrium (as this space is not considered an escape route) and positive pressure for internal assembly stations (as these spaces form part of the escape route). Note - Items in [brackets] refer to the agenda items. For further information concerning the above information, please contact ABS Regulatory Affairs Department at: tel: 201-226-5320; fax: -5314; Email: gshark@eagle.orgMSC – 75 th Session (15 - 24 May 2002)

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### 6 T HE N AVAL A RCHITECT J ULY /A UGUST 2003 

# S EVERAL interesting new safety technologies, including the now commonly used emergency low-location lighting in various forms, have resulted from some of the high-profile marine disasters of the last 26 years. These have particularly arrived since the Herald of Free Enterprise accident in 1987, but other important catalysts have included the fire

on Scandinavian Star in 1990, the Estonia disaster of 1994, and a relatively unpublicised incident on Nieuw Amsterdam in 2000, in which electro-luminescent low-location lighting was called into question.

Nevertheless, none of the new technologies can perhaps be considered so revolutionary (yet perhaps so simple) as a novel one being promoted today, which uses a human being's basic sense: sound. Audible alarms are, of course, in everyday use on board ships, but until now, none have been specifically harnessed to improve lifesaving; that situation is however changing with the introduction by a UK-based company named Sound Alert Technology of what is known as directional sound. Its technique, named Localizer, won the Royal Institution of Naval Architects' 2002 Safer Ship Competition.

Localizer, designed to help guide people to exits in the dark but, perhaps more importantly, under smoke conditions when exit and sign visibility is severely restricted, evolved from a chance incident that Professor Deborah Withington, a sound specialist at Leeds University, in the UK, experienced. While in a taxi, she heard a police or ambulance siren but realised that she could not identify the direction from which it came, due to the frequency used in such equipment.

The resulting technology (which was the subject of papers earlier this year at The Royal Institution of Naval Architects' Passenger Ship Safety conference and at the Warship 2003: Airpower at Sea conference*) instead uses broad-band, multi-frequency sound that is easily and quickly located by the human ear. All current alarms sound in the range between 1kHz and 2.5kHz because the human brain is very sensitive to these levels; unfortunately, no directional information is given at these frequencies, so a new spectral cue is required, hence the term broad band (frequencies from 20Hz to 20,000Hz). The special sound technique developed by Sound Alert Technology has been patented. Directional sound is already being introduced on land and is being considered for aircraft. IMO's concerns over the new generation of very large passenger liners led to a UK working party being set up (Maurice Storey and Alan Cubbin from the Maritime & Coastguard Agency, John Rugg, from Lloyd's Register, and John McNeece, formerly with the McNeece design consultancy). They considered sound to be a positive aid for evacuating public spaces and accommodation, and were optimistic over its future - and brought it to the attention of their IMO colleagues on the Large Passenger Ship Safety working group of the MSC.

Subsequent marine trials appear to have proved that sound is much more effective inguiding passengers to exits than photoluminescent and electro-luminescent lightbased systems. It is especially interesting to record that even technical staff intimately familiar with cabin arrangements on particular ships became totally disorientated in escape trials under smoke conditions.

A further driver for sound-based systems has been the very poor survivability time for humans in heavy toxic smoke - as little as 1.5min, according to some researchers. Indeed, 90sec is used by the aircraft industry as the measure of an aircraft's ability to quickly evacuate passengers.

Localizer beacons at strategic exit positions could be especially useful, believes Sound Alert Technology, in the large restaurants, casinos, and lounges that tend to characterise the modern generation of giant cruise liner and where escape points could be very difficult to find under smoke conditions. Under current SOLAS regulations, low-location lighting is not needed in such rooms - perhaps regrettably considering the large numbers of people congregating in them - but if it were to be made mandatory here, some believe that it would be ineffective, given the size of such spaces.

The UK MCA has taken a leading role in promoting sound technology, and a most interesting series of trials - devised in conjunction with Leeds University and the University of Strathclyde were carried out in June and October 2001. These took place, with the assistance of Tom McNeil, technical 

# Directional sound: an important new escape aid

Some figures and diagrams compiled by the UK MCA, which illustrate the attractions of directional sound in speeding escape from various parts of a ship.

* 'Directional sound evacuation - an improved system for way guidance from open spaces and exit routes on ships', by Prof Deborah Withington, School of Biomedical Sciences, University of Leeds, and Mike Lunch, Sound Alert Technology Plc. Presented at RINA headquarters, London, at The Royal Institution of Naval Architects' international conference on Passenger Ship Safety, March 25-26, 2003, and also at the Warship 2003 conference on June 25-26, 2003.

# W ITH recent increases in ship speed and propeller loading, there is increased danger of cavitation on the propeller and on appendages such as rudders, pods, and struts. The German model basin HSVA recently conducted several full-scale observations on semi-balanced rudders, revealing quite dramatic cavitation occurrences and cavitation-induced erosion damage.

Rudder cavitation erosion is of concern if it occurs within the range of rudder angles a=±5 deg while course-keeping. Different types of cavitation occurr on rudders, such as bubble, sole, gap, vortex cavitation, and cavitation caused by surface irregularities. HSVA believes that principal emphasis must be given to the area around the pintle. There, details of gap size and geometry, as well as exact workmanship, are of paramount importance.

Model tests Model tests can help in the early stage of design, especially when they are performed in a sophisticated test facility, and with a special aim to predict those types of cavitation occurrences. Rudder cavitation is not only influenced by the geometry of the rudder, but also by the inflow to the rudder and propeller. Therefore, tests in 3D inflow, behind the whole ship model, to give full propeller/hull interaction, are necessary to obtain a clear view of cavitation behaviour. If the danger of cavitation-induced erosion is large for specific areas such as the pintle, additional tests in a smaller tunnel with even higher Reynolds numbers are recommended. For the scenario mentioned above, part of a large rudder model was tested in HSVA's large cavitation tunnel. These tests could prove that there are mainly two critical areas where cavitation occurs: the gaps between the moveable part and the fixed part, and the areas downstream of the maximum thickness of the rudder sections. On the part-rudder model, complicated interactions between the flow through the gaps and the cavitation phenomena were observed.

One solution to improve cavitation behaviour is to keep cavitation - which cannot be avoided - away from the rudder surface in order to avoid erosion damage at those points, which are sensitive with respect to strength.To achieve this, use was made of wedgeshaped spoilers. The final rudder exhibits the following modifications (compared with the original rudder): • width alteration of the horizontal gaps and lower vertical gap in order to obstruct flow through gaps • spoiler at the lower end of the upper vertical gap (upstream of medium horizontal gap) • spoiler on the lower pintle, in order to direct cloud cavitation away from the rudder surface • fitting of a horizontal plate below the lower horizontal gap, extending downstream of the lower vertical gap.

These modified rudders have been in use on two ships for six months, and diver reports show an improvement regarding observed erosion damage.

Numerical investigations Before model tests, CFD calculations can be used to check cavitation behaviour of different rudder designs. With simple potential theoretical techniques, pressure distributions can be determined for the rudder profiles. Thickening was observed - often used because of strengthconsiderations - which leads to significant lowpressure drops in the region of the pintle bearing.

This is the most critical area of the rudder, and 3D viscous-flow calculations reveal complicated flow behaviour in this region. The water is sucked in, comparable to the behaviour of a scoop, into the gap between rudder horn and rudder blade. By a change of geometry in front of the gap, the quantity of water passing through the gap could be reduced, resulting in improved pressure distribution and therefore less cavitation danger. director of Caledonian MacBrayne, onboard two CalMac moored ferries (at-sea trials were not possible due to insurance restrictions). A total of 360 volunteers from local towns were recruited (all ages from 17-67), including blind and deaf people, and of both genders) to test Sound Alert Technology's system using theatrical smoke.

Apparently, real smoke with its toxic gascauses reflex closing of the eyes and is eyewatering, thus making escape even more difficult for passengers. Water-mist fire extinguishing systems - efficient though they are - also have a side-effect of making smoke fall to the deck quicker thus making public space exit even more hazardous. The CalMacferry trials also included tests with electroluminescent low-location light-based systems.

A second series of tests was also carried out in October last year at one of the Fincantieri shipyards on a new Carnival cruise liner, Carnival Conquest , shortly before delivery. For one of these, the nine-deck-high atrium was filled with smoke, and directional-sound alarms fitted to all 26 exits (20 of which were on the lower three levels, which created a confusing acoustic scenario). Apparently, volunteers found suitable exits very quickly.

For a cabin test in the complex crew area on the same ship, directional sound gave 55% reductions in average escape times when compared with low-location lighting. The public address and general alarm systems were operated in both sets of test but had no impact on the sound system's effectiveness.

The MCA appears to be impressed with such figures, given the limitations of trials scenarios; it is particularly interesting to note that this organisation records that low-location lighting was little used in the trials 'since in 3% density smoke, lighting assistance was not visible.'

One piece of legislation that may hasten the introduction of directional sound is the US Americans with Disabilities Act, which now applies to passenger ships; since blind people cannot see low-location lighting, directional sound would be a highly desirable feature. Meanwhile, last year, both the UK and German marine administrations have formally proposed directional sound evacuation to IMO as an equivalent to low-location lighting within SOLAS regulations. It is believed that Italy also supports the technology in principle.

Unfortunately, as most readers will know, the wheels of IMO turn exceedingly slowly and it could be several years for this equipment to be formally approved. Nevertheless, according to Sound Alert Technology, directional sound could still be introduced, using the provisions of SOLAS 2- II, Regulation 17; this allows for 'alternative design and arrangements' to be examined and approved, subject to fire safety engineering and risk analysis. However, some work by owners and yards would be needed.

Installation of a sound system could be very attractive to shipyards - it is much simpler than a low-location lighting design (some versions ofthe latter are understood to be very labourintensive to fit due to the many short sections, each of which must be wired from both ends for redundancy). It could readily be integrated within a public address or general alarm circuit using established SOLAS practice, using a second loop for redundancy in each fire zone and additional sets of loudspeakers. New direct-addressable digital technology for such circuits could also be included. An alternative is a free-standing arrangement, but this would have to go through a lengthy approval process.

A performance-based specification for directional sounders has recently been published by the British Standards Institution (PAS41:2003). Notwithstanding all this optimism, it seems likely at the present time that few operators will be bold enough to install the new technology prior to formal IMO approval - except perhaps to meet their obligations under disabilities legislation.

T HE N AVAL A RCHITECT J ULY /A UGUST 2003 

### 7 

# Reducing rudder erosion on fast ships

These diagrams illustrate an improved pressure distribution, thus less cavitation danger due to a change in rudder geometry.

# A P P L I C A T I O N S G U I D E



# Directional Sounder **with Voice Messaging**

### 1 

# A P P L I C A T I O N S G U I D E



# Directional Sounder **with Voice Messaging**

**Contents**
Section 1: Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Shortcomings of Traditional Methods

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Directional Sound Aids Evacuation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Directional Sound Influences Human Behavior

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
V oice Messaging Aids in Guiding Occupants

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Section 2: Why Directional Sound Works

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Psychoacoustic Theory

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Acoustic Performance in Building Applications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Bandwidth

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Sound Level Masking

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Average Ambient Sound. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Compatibility with Traditional Fire Alarm Notification Appliances

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Compatibility with Voice Evacuation Systems

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Reverberant Building Environments

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Section 3: Applicability of Building Codes and Standards

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Section 4: Locations for Directional Sounders

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
What are the exits where directional sounders can be used?

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
What are the areas of refuge or areas of rescue assistance where directional sounders can be used?

. . . . . . . . . . . . . . . . . . . . . 8
What are other means of egress components where directional sounders can be used?

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Locations that may not be suitable for directional sounders

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Section 5: Directional Sound Installations

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
General

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
T

ype 1 (Basic) Installation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
T

ype 2 (Enhanced) Installation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Special Considerations for Dead-Ends

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Section 6: Positioning Directional Sounders on Wall and Ceiling Surfaces

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Section 7: Frequently Asked Questions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Section 8: Glossary

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
References

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
List of Illustrations

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

This application guide provides information to building design professionals, specifying engineers, fire alarm system installers, andenforcement authorities regarding 1) the technical or psychoacoustic basis for directional sound technology, and 2) the implementation of directional sounders as an aid to locating exits, egress routes or refuge areas.

Directional sounders, integrated with the building’s firealarm system, are a supplemental, audible means of identifying exits and egress routes and can provide a means of overcoming the limitations of current exit signage and alarm signals. The directional sound from the devices does not conflict with the traditional audible alarm signals, whether horns or bells; however, they are not a substitute for these traditional fire alarm devices. (Directional sounders are NOT intended to replace or be a substitute for fire alarm system notification appliances.) There may be potentialcompatibility issues with the voice speakers for which guidance is provided in the following sections of the guide.


### Shortcomings of Traditional MethodsFire alarm systems designed to initiate evacuation or relocation of occupants use audible and visible notification appliances that occupants will hear or see when the fire alarm system operates. Depending on the particular fireemergency plan, the occupants may be required to evacuate or relocate immediately or prepare for such evacuation or relocation. Oftentimes, occupants may not be familiar with the building and its associated emergency egress routes and may have to rely on exit maps, markings, or signage to guide them to an exit, refuge area or other means of egress.

The traditional maps, markings and signage required by codes provide occupants a visible means for locating or finding a path to safety. Generally, exit signage will be the primary means for locating an exit, refuge area or other means of egress. If an emergency plan has been prepared, it may include diagrams showing the locations and routes to exits. Occupants, however, may not have had an opportunity to study and understand such a diagram or cannot visualize an actual escape route as depicted on such a diagram. There are other limitations to the way building occupants identify the means to reach a point of safety in a buildingduring a fire or other emergency that necessitates evacuation or relocation. Persons with visual disabilities will have difficulty with emergency information that relies on visual cues. The signals that alert the occupants to an emergency event and suggest the need to evacuate usually are both audible and visual. Illuminated exit signs serve only as a visual cue. Other weaknesses are that the illuminated front of exit signs may often compete with nearby bright lights or other visually distracting elements. Exit signs may be inadvertently blocked from view due to renovations or remodeling of building or tenant spaces. Of course, at the time of a fire, when exit signs are most needed, it is possible for smoke to obscure exit signs and the location of exit doors.



### Directional Sound Aids Evacuation Directional sound technology offers a solution to improve the exit or relocation situation for building occupants. To help occupants in finding their way to an exit, refuge area or other means of egress, directional sounders integrated with the fire alarm system provide additional auditory information that can assist or aid occupants in locating escape routes without conflicting with the traditional fire alarm system notification appliances such as bells or horns. Directional sounders utilize a broadband acoustic characteristic that is distinctive from the audible sounds of bells, horns, or voice speakers. Directional sounders are intended to operate simultaneously with the traditional fire alarm notification devices and to be wired as part of the fire alarm system notification circuits. Again, it is important to note that directional sounders are NOT intended to replace or be a substitute for notification appliances required by building or fire codes. They are, however, to be installed on the notification appliance circuits, in accordance with NFPA 72, National Fire Alarm Code.

Experts and researchers in the area of human behavior have recognized two phenomena that appear common in evacuations of buildings. 1,2,3 First, is that occupants tend to exit a building by the route familiar to them, which may be the same route they used to enter a building. Second is the concept of “learned irrelevance” of exit signs, where people continually exposed to exit signage seldom consider **Section 1** 

## Introduction **Preface**

This installation guide is the first effort of System Sensor to address the application of its new directional sounders for buildings and structures. The technology and initial applications of directional sound were developed at the University of Leeds under the supervision of Professor Deborah Withington and have become an accepted technology by internationalorganizations as an aid to evacuation. While directional sound technology is a recognized and accepted technology overseas, System Sensor considered it important and appropriate to obtain North American expertise to review the technology and assist with the development of this application guide. Experts with backgrounds in acoustic engineering, human behavior during fire and evacuations, building and fire codes; and fire protection engineering were key to this effort.

This guide intends to promote an understanding and awareness of the benefits and capabilities of directional sound. A primary focus of this guide is to provide information important to building design professionals, specifying engineers, fire alarm system installers, and enforcement authorities that will increase the probability of a proper installation and reduce the possibility of misapplication of directional sounders in the commercial marketplace. As with any new technology, it is anticipated that the role directional sound will play as a safety enhancement in buildings and structures will continue to develop and that this installation guide will be revised and updated to reflect modifications or improvements of the product features and refinements in directional sound applications in coming years. February 2007



### 2 **To support the development effort for this guide**  and other work, Schirmer Engineering Corporation, serving as the lead fire engineering consultant, assembled a team of experts that included both
in-house staff and several key individuals recognized for their particular expertise in the areas of human behavior, fire protection engineering, and design of acoustic environments. A special thanks to the following for
their contributions to date:

**John L. Bryan, DEd.,** Professor Emeritus, Department of Fire Protection Engineering, University of Maryland, and
a student and observer of
human behavior in fire.

**Guylene Proulx, Ph.D.,** Senior Scientist, National Research Council of Canada, and an international expert on human
behavior in fires.

**Robert P. Elfering, P.E.,** an acoustical engineer with Shiner & Associates, a nationally recognized firm specializing in acoustics for commercial, multi-family, residential, institutional, educational, industrial and
recreational facilities.

**Daniel J. O’Connor, P.E.,** fireprotection engineer. VicePresident of Engineering for Schirmer Engineering and the Chair of the Society of Fire Protection Engineer’s Task Group on Human Behavior.
Member of the NFPA 72 Committee on Initiating
Devices.

The work of these individuals
serves not as an endorsement of the technology, but as independent sources
for validation of the appropriateness of directional
sound and the identification of
limitations and considerations in application.S Y S T E M S E N S O R

the information it is intended to convey, i.e. the identification of alternative exits and exit access. In an emergency, they fail to respond to signage pointing to alternate means of egress, instead opting for the exits with which they are familiar.

Directional sound offers a means for reducing these tendencies and providing an additional stimulus in the form of sound cues that draw attention to otherwise ignored egress routes and exit locations. In this way, directional sound can serve to increase exit utilization by encouraging the use of all exit facilities and speeding total evacuation when needed.



### Directional Sound Influences Human Behavior The broadband sound pulses of directional sounders make use of our natural ability to localize sound sources when provided with the appropriate spectral and temporal cues. To be of benefit, the technology requires occupants tomake use of these supplemental audible cues in a manner that enhances their behavior during an evacuation. The psychoacoustic response to directional sounders has been shown in numerous exercises and research studies to lessen the time required for evacuation and to effectively assist occupants searching for egress routes and exits. Numerous research studies have shown that directional sounders improve the flow of people towards exits, and they improve evacuation efficiency. While many of these realistic exercises were conducted on passenger ships and ferries, the results are broadly applicable to evacuation and relocation scenarios in buildings.

Prompted by a 1990 fire that resulted in 158 deaths aboard the Scandinavian Star ferry in Norwegian waters, numerous evacuation trials have been conducted by the University of Leeds and the University of Strathclyde between 2000-2003. The various trials involved numerous scenarios such as evacuations with and without directional sound, evacuations with low visibility conditions created by use of theatrical smoke, and a variety of room and complex corridor arrangements. In smoke-filled scenarios with little or no visibility of exit signs, directional sound demonstrated its benefit to provide cues that significantly reduced the time for subjects to find the nearest exit and to find the exits without retracing their steps.

The egress behavior of subjects in normal visibility did not show the same extent of improvement in egress times, but subjects indicated the sound cue as a confirming aid in finding the exit. A more dramatic result was evident in evacuation trials when subjects received a briefing on themeaning of the directional sound. In these trials with briefings, the subjects consistently performed better at finding the closest exit and exhibited faster exit times.


### Voice Messaging Aids in Guiding Occupants A question often asked about directional sounders is how building occupants will know how to react when they hearthe sound. Although the sound is intuitive to many people, an enhancement made to directional sound technology is the addition of voice messaging. In between four second bursts of directional sound, an alert message in the form of a recorded voice message can be used. The purpose of the voice message is to instruct the occupants of what action to take as they approach the directional sounder.This messaging will allow them to react quickly and confidently without training or prior knowledge of directional sound. The messages will instruct occupants that they are approaching stairs going up, stairs going down, an area of refuge, or the exit.



### 3E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

Today, there is a significant body of literature and texts regarding the human mechanism of hearing and the science of acoustics. Since approximately the 1980’s significant studies and technical work have been done toquantify and further understand the psychoacoustic mechanisms that allow the human ear to pinpoint or localize the source of sounds. 4,5,6,7 The following section summarizes the psychoacoustic basis for sound localization, describes why directional sound works and why directional sound iscompatible with traditional fire alarm signals and reverberant building environments.



### Psychoacoustic Theory The ability to pinpoint the location of a sound source is based on the physics of sound and the physiology of the human hearing mechanism. The brain processes a large amount of neural signals, some of which provide cues to the sound source’s location.

People are able to hear sound ranging from about 20 Hz to 20,000 Hz, although as we age this range diminishes. Many fire alarm signals are pure tones or narrowband sound in the 1000 Hz to 3000 Hz range, to which the humanear is particularly sensitive as far as loudness is concerned. Unfortunately, pure tones in this frequency range provide only limited localization information.

The primary localizationcues are provided by interaural time differences (lower frequencies), interaural intensity differences (mid to higher frequencies), and thehead-related transfer function (higher frequencies). In enclosed spaces that may be somewhat reverberant, the precedence effect provides directional information.Each of these four psychoacoustic phenomena is discussed briefly below:

The interaural time difference (ITD) and interaural intensity difference (IID) are termed binaural cues because they depend on both ears separated by the width of the head. At lower frequencies (longer wavelength) the time delaybetween arriving sound signals is detectable. Interauraltime difference is most evident in frequencies below about 1000 Hz with clicks or short bursts of sound. At higher frequencies (shorter wavelength) the loudness/intensity differences between the ears is more noticeable because of partial shielding of the more distant ear by the head. Interaural intensity differences are most evident for frequencies above 3000 Hz. Figure 1 depicts the binaural cues – ITD and IID.

The head-related transfer function (HRTF) relies on the effect of the external ear on perceived sound. The HRTF describes the transforming effect of the head, torso and external ear on sound as it travels from the sound source to the ear canals. The shape of the ear attenuates some frequencies and amplifies others, filtering the sound field as depicted in Figure 2. This filtering effect is mainly due to directional reflection effects the pinna and concha of the outer ear have on the incident sound field. The HRTFchanges depending on sound source location, providing an additional localization cue. HRTF operates over a range of frequencies, but seems to be most effective in the 5,000 Hz to 10,000 Hz range. Combined with the listener’s head motion, HRTF provides an independent localization method to complement ITD and IID capabilities.

In addition to confirming ITD and IID localization cues, the HRTF provides vital localization information when the sound source is near the plane equidistant from each ear, i.e. directly in front, behind or above the head. In these situations ITD and IID do not provide distinct localization cues because each ear is equidistant and unshielded from the source. Front-back and vertical localization of the sound source is made possible by the HRTF.

The precedence effect is important for discriminating between the direct sound signal and reflected sound, a common situation within buildings. The ear is capable of discerning and fixating on the first sound received (line-of-sight direct signal) and disregarding later signals (reflected sound). The acoustical signal arriving first at the ears suppresses the ability to hear other signals (including reverberation) that arrive up to about 40 milliseconds after the initial signal.

All of the above cues are utilized simultaneously when the source signal is broadband sound containing a range of low and high frequencies. The combination of different cues provides reinforcement and redundancy of information to enhance the ability to locate the sound source. Broadband sound tends to eliminate potential ambiguities that occur for pure tone or narrowband sound sources.

For further information regarding the theoretical aspects of sound localization, see the list of sources in the enclosed reference section.


### Acoustic Performance in Building Applications The directional sound device enables ready localization by providing bursts of broadband sound rather than a traditional pure tone signal. Intended to be used as a supplement to traditional alarm signals, a directional sounder provides an additional guidance cue. Parameters that account for the performance of directional sounders in buildings are as follows:

Bandwidth Bursts of directional sound cover a broad enough rangeto enable binaural localization cues and HRTF localiza**Section 2** 

## Why Directional **Sound Works**

Figure 1. Interaural time and intensity differences of sound.

Figure 2. Examples of frequency dependent attenuation for sources in front, above and behind the listener.


### 4S Y S T E M S E N S O R

tion cues. A low frequency content enables easy detection of interaural time differences, while a medium to high frequency content facilitates discrimination of interauralintensity differences. Low to high frequency content facilitates discrimination using the HRTF.

Directional sounders contain frequency content extending over almost all of the entire range discernible by the human ear. This wide band type of frequency content is often referred to as “white noise”. This wide spectral range of broadband sound is important for providing redundancy and reinforcement of perceived sound signals, enabling localization cues due to all binaural, transfer function, and precedence effect mechanisms.

Sound Level MaskingThe concept of “masking” is important when determining appropriate sound pressure levels for alarm signals. Masking is an acoustic process in which the audibility of one sound (the signal) is affected by the presence of another sound (the masking sound). Masking sound, if it is loud enough and has similar frequency content, can partially or totally hide the signal sound.

Typical building environments have background noise due to ventilation and other mechanical systems, telephones, conversation, etc. In order to be clearly audible, the soundlevel of alarm signals should exceed background noise levels by at least 10 dB, preferably by 15 dB. The higher alarm signal level is required so that it is not hidden (masked) by other naturally occurring sound sources.

Average Ambient Sound Ambient sound levels should be determined in order that the sound levels of directional sounders can be set at appropriate sound levels. Figure 3 from Appendix A to NFPA’s Fire Alarm Code shows examples of what average ambient sound levels may be for different applications. 8 The examples should not be used as a substitute to taking actual on-site measurements. In the same appendix, the following is stated regarding the measurement of average ambient sound:

“When surveying the ambient sound levels to establish the increased level at which a notification appliance will properly function, the sound source needs to be averaged over a longer period of time. Moderately priced sound level meters have such a function, usually called ‘L eq ’ or ‘equivalent sound level.’ For example, an L eq of speech in a quiet room would cause the meter movement to rise gradually to a peak reading and slowly fall well after the speech is over. “L eqreadings can be misapplied in situations where the background ambient noises vary greatly during a 24-hour period. L eq measurements should be taken over the period of occupancy.” 9

Compatibility with Traditional Fire Alarm Notification Appliances Directional sounders are envisioned as an additional evacuation aid to be used with, not as a replacement for,traditional notification appliances (bells, horns and speakers). Hence, during the period that people are exiting or relocating, there will be two dominant alarm system sound sources, both of which should be audible. Since both traditional alarms and directional sounders can comfortably exceed mostcommon background noises, masking of alarm signalsby ambient noise is not normally an issue. Traditional alarm devices have a strong tonal content as opposedto the more even, broadband content of a directional sounder.

Figure 4 compares the spectrum of a typical firealarm signal at a high setting with the spectrum of the directional sounder at a lower power setting. Note that while the typical alarm signal clearly dominates at 3000 Hz and to a lesserextent at upper harmonics, the broadband directional signal of the directional sounder is 20-30 dB louder than the fire alarm over most of the range. And although the fire alarm may have an overall A-weighted sound level 20 dBA or morehigher than the overall Aweighted sound level of the directional signal, both alarms are audible.

The reason that the directional signal does not actually have to be higher in overall sound pressure level than the traditional alarm signal is because the traditional alarm will only mask a narrow range of frequencies near the traditional alarm’s dominant pure tones. Since the directional sounder has a wide spectral range and is generated in short sound burstsgiving timing, intensity and HRTF cues, most of the broadband sound will be audible in the presence of higher pure tone sound levels.

Reverberant Building Environments Due to the precedence effect, the ear can discriminate the direct sound signal from reflected signals in enclosed
spaces.

The directional sounder’s pulsing broadband directional signal makes good use of the precedence effect and can compensate for less than optimum listening conditions. Even in highly reverberant spaces, in which every surface was sound reflective, test subjects have had no problem determining the location of directional sounders.

Most building interiors have a blend of sound reflective and sound absorbent finishes. However, even under the semi-reverberant conditions of certain building interiors such as gymnasiums and lobbies finished in concrete **Location Average Ambient**  **Sound Level** Business occupancies 55 dBA Educational occupancies 45 dBA Industrial occupancies 80 dBA Institutional occupancies 50 dBA Mercantile occupancies 40 dBA
Piers and water-surrounded structures 40 dBA Places of assembly 55 dBA Residential occupancies 35 dBA Storage occupancies 30 dBA Thoroughfares, high density urban 70 dBA Thoroughfares, medium density urban 55 dBA Thoroughfares, rural and suburban 40 dBA Tower occupancies 35 dBA Underground structures and windowless buildings 40 dBA

Vehicles and vessels 50 dBA

Figure 3. Typical ambient sound levels



### 5 Figure 4. Frequency response of traditional fire alarm signals versus directional sounder 3 kHz Fire Alarm

Directional Sounder 

### Directional Sounder vs. Fire Alarm Signal

**Directional sounder at 66dBA and fire alarm horn at 86dBA measured at 10 feet horizontally in an anechoic chamber** 

**Frequency (Hz)**E X I T P O I N T TM D I R E C T I O N A L S O U N D E R



### 1 Because directional sounders are wired as part of abuilding’s fire alarm system, the codes and standards applying to fire alarm installations also apply to directional sound. This is the case both when directional sound is added to existing firealarm systems or when it is incorporated into new installations. When an existing fire alarm system is altered to incorporate directional sound, it may be necessary to make other alterations or replacements so as to have the system conform to current standards.

The application of directional sound requires a basic understanding and knowledge of the means of egress, means of escape and area of refuge provisions found in the model codes for buildings and life safety. There are two independent organizations in the United States, the National Fire Protection Association (NFPA) and the International Code Council, Inc. (ICC), that write model building and fire codes intended for legal adoption by local governments (cities, counties, states). Local jurisdictions may adopt these model codes without change or alter them to suit their preferences. Some cities write their own codes, and many jurisdictions may still be operating under model codes promulgated by ICC predecessor organizations. Thelocal authority having jurisdiction (AHJ) should be consulted for information on specific local regulations.

National Fire Protection Association (NFPA) Batterymarch Park, Quincy, Massachusetts 02169-7471block, terrazzo, drywall, glass, etc., the sounder’s directional signal will be easily locatable.

Compatibility with Voice Evacuation Systems Where directional sounders and voice evacuation systemsemploying speakers are utilized within the same occupancy the directional sounders can reduce the speech intelligibility of the voice speakers. For this reason it is recommended that when both systems are utilized in the same installation that the two systems are not operated simultaneously. Where simultaneous operation of the voice evacuation speakers and the directional sounders cannot be avoided there are system design guidelines that can be followed to reduce the effects of the directional sounders on the intelligibility of the voice speakers.

The factors influencing the loss to speech intelligibility include; the intelligibility of the voice system without thedirectional sounders operating, the amount of reverberation present, and the sound pressure differential of the directional sounders vs. the voice speakers.

In general, if the speech intelligibility of the voice evacuation system before adding directional sounders is very good then the effects of the directional sounders will be minimized.Thus, improving the speech intelligibility of the voice system will minimize the loss from the directional sounders. This can be accomplished by using high quality speakers, using more speakers, and/or increasing the sound pressure of the voice system relative to ambient sound levels.



### 6 High degrees of reverberation will result in greater loss to intelligibility of voice systems when directional sounders are present. The degree of reverberation of a space will depend on the room characteristics such as the volume, the nature of finishes and furnishings and the number of occupants. Spaces with acoustically soft surface materials (textured ceiling tiles, drapes, carpet) will absorb sound and be less of a reverberant environment than spaces with acoustically hard surfaces (concrete, plaster, glass) which reflect sound around a space. To minimize the effects of the directional sounders, avoid using directional sounders inacoustically hard environments or reduce the sound pressure of the directional sounders in these areas. Sound pressure of the directional sounders can be reduced by either reducing the power setting of the sounders in the area or carefully selecting the locations of the directional sounders to increase the separation of the directional sounders and reverberant areas. If the reverberation in an area is toogreat it will not be possible to achieve good speech intelligibility even without the directional sounders.

In locations where the sound pressure of the voice system is comparable to the sound pressure of the directional sounders the reduction of intelligibility will be increased. In general, this will only occur in close proximity to the directional sounders. Speech intelligibility can be improved by adding additional speakers to these locations. This will increase the sound pressure of the voice system in these areas. In general, adding a second speaker will result in an increase of 3dB.

**Section 3** 

## Applicability of **Building Codes And Standards**  NFPA publishes codes and standards concerning all areas of fire protection. The key documents published by NFPA that define the requirements for exits and refuge areas are:

NFPA 101, Life Safety Code – NFPA 101 specifies the requirements for means of egress, means of escape and areas of refuge for new and existing buildings depending on the occupancy classification of a building or portion of a building.

NFPA 5000, Building Construction and Safety Code – NFPA 5000 is model building code for new construction that specifies the requirements for exits and refuge areas based on the occupancy classification of a building or portion of a building.

NFPA 1, Uniform Fire Code – NFPA 1 is a fire prevention code that incorporates provisions from prior editions of NFPA 1 and provisions of Western Fire Chiefs Association Uniform Fire Code. The document contains provisions for the means of egress and means of escape for new and existing buildings consistent with NFPA 101.

NFPA various other documents – Other NFPA documents may contain specific requirements for means of egress and means of escape.

Two other NFPA documents are of particular interest in relation to directional sounder installations:

NFPA 70, National Electrical Code – This is one of NFPA’s most widely recognized documents, covering all aspects ofS Y S T E M S E N S O R

electric wiring installations, including those for fire alarm systems. It has been adopted by ICC (see below) as part of its series of codes.

NFPA 72, National Fire Alarm Code – NFPA 72 covers all aspects of fire alarm installations, including detection devices, manual fire alarm stations, alarm notification devices, central station services, power supplies and arrangement of circuits. It has been adopted by ICC (see below) as part of its series of codes. The 2007 Edition of NFPA 72 provides guidance on installing and maintaining directional sounders in Chapters 6 (Protected Premises), Chapter 7 (Notification Appliances) and Chapter 10 (Testing and Maintenance.)

International Code Council, Inc. (ICC) 5360 Workman Mill Road Whittier, California 90601-2298 The ICC is the successor organization to the three regional model code development organizations:

Building Officials and Code Administrators (BOCA) International Conference of Building Officials (ICBO) Southern Building Code Congress International (SBCCI)

The ICC was formed for the purpose of combining the above three organization’s codes into a single set of model building and fire codes. The first combined documents included the ICC’s 2000 International Building Code and 2000 International Fire Code, which define requirements for exits and refuge areas. Many jurisdictions have or are in the process of adopting the ICC’s building and fire codes, however, the BOCA National Building Code, the ICBO Uniform Building Code, and the SBCCI Standard Building Code continue to be used in many jurisdictions.

ICC documents that may contain exiting provisions or thatmay affect fire alarm (and directional sounder) installations include:

• International Building Code

• International Fire Code

• International Existing Building Code

• International Residential Code for One- and TwoFamily Dwellings

• International Property Maintenance Code • ICC Electrical Code – Administrative Provisions (adopts by reference NFPA 70)

• International Performance Code for Buildings and

Facilities

Federal Accessibility Laws: Americans with Disabilities Act Accessibility Guidelines (ADAAG) Fair Housing Accessibility Guidelines (FHAG) In addition to any NFPA or ICC documents that may be legally adopted and applicable to building design are the Federal requirements applicable to buildings. The Americans with Disabilities Act (ADA) and the Fair Housing Amendment Act (FHA) are federal regulationsthat affect building construction as it relates to accessibility for persons with disabilities. Exit design, refuge area design and fire alarm system design all are impacted by these federal laws.

Currently, NFPA and ICC documents address accessibility provisions for people with disabilities which are modeled on the requirements of the Americans with Disabilities Act Accessibility Guidelines (ADAAG) and the Fair Housing Accessibility Guidelines (FHAG). Compliance with NFPAor ICC documents, however, does not constitute compliance with federal requirements and designers are guidedto review and understand both ADAAG and FHAG requirements as they may apply to exit design, refuge area design and fire alarm system design. Additionally, it is noted that in the case of public service facilities (Title II of the ADA) an alternative design standard can be applied in lieu of the ADAAG. This standard is the Uniform Federal Accessibility Standards (UFAS).

Underwriters Laboratories, Inc. (UL) UL is a testing laboratory that evaluates components of fire alarm systems to verify compliance with NFPA requirements and their own standards. Equipment such as directional sounders that pass UL tests are identified by a label or listing. UL publishes an annual directory that lists equipment bearing the UL label. In the case of a directional sounder, the applicable test standard is UL 464, Audible Signal Appliances. Under this standard, a directional sounder is listed as a supplemental notification appliance.



### What are the **exits where directional**  **sounders can be used?** Often, the simplest way to identify the exits in a building is to look for the exit signs. With few exceptions, exit signswill be found at the termination of exit paths, such as exterior doors at ground level, doors into enclosed stairways, doors leading horizontally into an adjoining building or fire area, and doors leading to exterior stairways and fire
escapes.

The exit as defined by NFPA 101 (2003 ed.), NFPA 5000 (2003 ed.) and the 2003 ICC International Building Code is one specific travel element or section of the means of
egress which is comprised of three distinct elements that are 1) the exit access, 2) the exit, and 3) the exit discharge. The exit is the primary focus of a basic installation of directional sounders, and most often this will be at doors leading to the exterior, at doors into stairways, or at horizontal exit doors. Basic and enhanced installations are more fully described in the section of this guide entitled “Directional Sound Installations.” The three basic elements of the means of egress and the specific concepts of an exit passageway and a horizontal exit found in NFPA and ICC documents are described in the table on page 8.

Both code organizations use effectively the same concept in defining the exit. Figures 5 and 6 graphically illustrate the concepts of exit access, exit, and exit discharge.

The code definitions on page 8 provide the generic description of an exit, which in more specific terms, may be found as one of the following types of exits described and illustrated below.

• Door s leading directly to the outside at grade

• Doors leading into a protected passageway which leads

to the outside at grade **Section 4** 

## Locations for **Directional Sounders**

7E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

Enclosed Exit Stair Exit Access Ends at Exit Doorupdownupdown

Enclosed Exit Stair X X X

Exit Access Starts At Any Point

X X

X

Exit Access Routes

Figure 5. Exit access starts from any normally occupied point on a floor and ends at the door leading into an exit.

Exterior Exit Stairway

Exit (From Grade Level) Interior Exit Stairway

Exit Discharge

Figure 6. Different types of exits illustrated. • Interior stairs enclosed by fire rated construction, which includes

– Smokeproof towers – Pressurized stairways

• Exterior stairs isolated from the building interior with fire

rated or protective construction

• P assageways enclosed by fire rated construction (should

not be confused with corridors) • Horizontal exits

• R amps enclosed by fire rated construction

• Escalators enclosed by fire rated construction • Fire escapes

• Other special exits – Although the above listed items represent common types of exits found in buildings or structures, there are other types of open or unenclosed routes that may legally constitute an exit. These are sometimesthe result of unique building conditions, a code equivalency or performance-based building design.

Figure 7 illustrates one of the most common arrangements of an exit, the fire resistive enclosed stair. Figures 8 and 9 are enhanced versions of the same type of stair exit. Figure8 illustrates a smoke-proof tower arrangement that represents an enclosed stair preceded by an open-air balcony or vestibule. Similarly, Figure 9 shows an enclosed stair accessed via a vestibule that is mechanically ventilated.



### What are the **areas of refuge or**  **areas of rescue assistance**  **where directional sounders can be used?** In 1990 the Federal Government passed the Americans with Disabilities Act which was the first large scale legislation to contain provisions for accessible means of egress for people with physical disabilities or mobility impairments, such as occupants using wheelchairs, walkers, crutches or canes. During the 1990s and up to the present time both the NFPA and ICC (and its predecessor organizations) have developed criteria for accessible means of egress consistent with the federal laws. In addition to federal law, both NFPA and ICC codes require that newly constructed buildings have accessible means of egress as defined by NFPA and ICC documents. An element of an accessible means of
egress is often a specially provided space in the building 

### 8 **Basic Concepts – Means of Egress**
**NFPA Definitions ICC Definitions**  Means of Egress – A continuous and unobstructed way of travel from any point in a building or structure to a public way consisting of three separate and distinct parts: (1) the exit access, (2) the exit, and (3) the exit discharge. Means of Egress – A continuous and unobstructed path of vertical and horizontal travel from any occupied portion of a building or structure to a public way. A means of egress consists of three separate and distinct parts: the exit access, the exit and the exit discharge
Exit Access – That portion of a means of egress that leads to an exit. Exit Access – That portion of a means of egress that leads from any occupied portion of a building or structure to an exit.
Exit - That portion of a means of egress that is separated from all other spaces of a building or structure by construction or equipment as required to provide a protected way of travel to the exit discharge. Exit - That portion of a means of egress that is separated from other interior spacesof a building or structure by fire-resistance-rated construction and opening protectives as required to provide a protected path of egress travel between the exit access and the exit discharge. Exits include exterior doors at ground level, exit enclosures, exit passageways, exterior exit stairs, and horizontal exits. Exit Discharge – That portion of a means of egress between the termination of an exit and a public way. Exit Discharge – That portion of a means of egress system between the termination of an exit and a public way Exit Passageway - NFPA does not maintain a formal definition of exit passageway but does explain the concept in the Appendix of NFPA101 as follows: An exit passageway serves as a horizontal means of exit travel that is protected from fire in a manner similar to an enclosed stair. Exit Passageway – An exit component that is separated from other interior spaces of a building or structure by fire-resistance-rated construction and opening protectives, and provides for a protected path of egress travel in a horizontal direction to the exit discharge or the public way.
Horizontal Exit - A way of passage from one building to an area of refuge in another building on approximately the same level, or a way of passage through or around a fire barrier to an area of refuge on approximately the same level in the same building that affords safety from fire and smoke originating from the area of incidence and areas communicating therewith. Horizontal Exit- A path of egress travel from one building to an area in another building on approximately the same level, or path of egress travel through or around a wall or partition to an area on approximately the same level in the same building, which affords safety from fire and smoke originating from the area of incidence and areas communicating therewith.S Y S T E M S E N S O Rupdown

Fire Door Fire Rated Enclosed Stairway

Figure 7. Fire-rated enclosed stair.

Fire Rating Based On Number Of Stories

up downupdown

Fire Rated Exit Passageway (Penetrations Restricted)

Corridor

Fire Rated Door

Figure 12. Floor exit arrangement showing a fire rated exit passageway leading to an enclosed exit stair. The doorway into the exit passageway constitutes the point of entry into the exit.updown

Fire Door Mechanical Ventilation

Shaft Fire Rated Enclosed Stairway

Figure 9. Smokeproof tower, mechanically vented. 2 Hour Fire Barrier Doors are Automatic or Self Closing Fire Doors up down up

down

Enclosed Exit Stair

Enclosed Exit Stair

Figure 10. Building floor area served by enclosed exit stairs and horizontal exit fire barrier wall. Door openings through the 2-hour fire barrier qualify as exits.

9

8

7

6

5

4

3

2

1 6

5

4

3

2

1 Horizontal Exit from One Building to Another Via Bridge

2 Hour Fire Barrier Wall Either or Both Sides

Figure 11. Illustration of a horizontal exit using a bridge between two buildings.



### 9 Open to Outsideupdown Fire Rated Enclosed Stairway

Fire Door

Fire Door

Figure 8. Smokeproof tower.E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

called an area of refuge. In fully sprinklered buildings, anysprinklered story or floor of the building is effectively considered an area of refuge and; therefore, the areas of refuge discussed herein are typically found in recently constructed(i.e. buildings built after 1990) non-sprinklered, multistory buildings. Buildings built prior to the passage of the Federal ADA laws typically are not required to have areas of refuge; however, state or local governments may have passed laws or ordinances that required areas of refuge in sprinklered and non-sprinklered buildings built before and after 1990. Where areas of refuge have been designated, they typically will be a part of or immediately adjacent to a stairwaythat is part of the means of egress. As such, the directional sounder at the entrance to the stairway will serve to identify the location of the area of refuge – see Figure 13, below. A different situation exists when an elevator serving as an accessible means of egress has been provided, and includes the elevator lobby as an area of refuge as shown in Figure 14. Such means of egress elevators and associated refuge areas are now required by ICC in non-sprinklered buildings having more than four levels above or below the level of exit discharge (the ground floor, usually), and they are permitted by NFPA. In such cases, a directional sounder must differentiate between access to an area of refuge solely intended for those requiring assistance for exiting and access to an exit stairway.

An unusual condition that may be encountered is where an elevator is also part of the required means of egress. This may occur in a tower structure, such as an airport traffic control tower. In these cases, the access to the elevator is treated in the same manner as access to a stairway, and a directional sounder at the entrance to the elevator lobby orthe elevator door, itself, may be appropriate. Using elevators as one of the recognized means of egress is likely to become more common in the future as codes are changed to reflect the reality of trying to evacuate tall buildings in an emergency.


### What are other means of egress components **where directional sounders can be used?** In addition to exterior doors, doors leading to stairs andramps, and other common components of the exits previously identified, other types of exits and other components of the exit path may need directional sounders to assist in evacuation or relocation. In older buildings, fire escapes still are considered to be part of the required exit system, and they are likely to be identified by exit signs at the door or window leading to the fire escape, as well as in **Basic Concepts – Area of Refuge**

**NFPA Definitions ICC Definitions** 
Accessible Means of Egress – A means of egress that provides an accessible route to an area of refuge, a horizontal exit, or a public way. Accessible Means of Egress– A continuous and unobstructed way of egress travel from any point in a building or facility that provides an accessible route to an area of refuge, a horizontal exit, or a public way.
Area of Refuge – An area that is either (1) a story in a building where the building is protected throughout by an approved, supervised sprinkler system and has not less than two accessible rooms or spaces separated from each other by smoke resisting partitions; or (2) a space located in a path of travel leading to a public way that is protected from the effects of fire, either by means of separation from other spaces in the same building or by virtue of location, thereby permitting a delay in egress travel from any level. Area of Refuge – An area where personsunable to use stairways can remain temporarily to await instructions or assistance during emergency evacuation.

up down 30 × 48 Wheelchair Space Area of Refuge Adjacent to Means of Egress Stairway48 Minimum48 Minimumupdown

Area of Refuge In a Means of Egress Stairway 48 Minimum

48 Minimum

Figure 13. Areas of refuge at stairways. 

### 10 Accessible Elevator



### Xupdown Exit Access Starts at Any Point Protected Area of Refuge



### X

**X** Accessible Exit Access Routesupdown

Figure 14. Area of refuge at elevator lobby, serving an accessible means of egress elevator.S Y S T E M S E N S O R

the corridor access to the fire escape. At both locations, directional sounders will be useful in supplementing the visual signage.

Exit access includes the path of travel from any point in the building along aisles and corridors to an exit. A Type 2 installation that provides sounders both at exits and in the exit access route is described in the section “Directional Sounder Installations,” following. Directional sounders in a Type 2 installation may be appropriate wherever supplemental signage is used to assist in identifying the exit access route.

Most commonly, supplemental exit signage (typically, an exit sign with or without single or bi-directional arrows) is used at corridor intersections where the direction to the exit is not obvious and for long stretches of corridors or walkways where the exit sign at the exit is too far away tobe readily seen. Not all of these sign locations are appropriate for a sounder — sound is omnidirectional and travels around corners. Each potential sounder location has to be analyzed individually. Sounders spaced too closely may cause confusion. See “Directional Sound Installations” for guidance.

Open stairways (i.e. stairways not within a fire-resistive enclosure) and walkways, under certain circumstances, may also be designated as a primary means of egress andare likely to be designated by exit signs. Directional sounders may be appropriate at these locations.

“Dead-ends” and common paths of travel are other components of the means of egress. The former (see definition, this page) can be a problem if a person becomes disoriented or fails to see an exit sign at the open end of a corridor that has only one way out. A directional sounder at the point where the “dead-end” corridor joins with paths to two (or more) exits will help to orient the occupant and lead the occupant away from a situation where the person can become trapped at the far, dead-end of the corridor.

Common paths of travel may include exit access travel in a dead-end corridor, but the most common situation is the travel from any point in a room to the room’s only door. Because two separate paths to an exit are not available within the room, that portion of the means of egress is a common path of travel. The codes limit the length of such common paths of travel, depending on the occupancy. In complicated situations, as for instance, when the space is broken up by filing cabinets, library shelving or other such obstructions, a directional sounder at the room’s exit door will better define the way out than an illuminated exit sign. Even though under such conditions an exit sign may be required only if the room is intended to be occupied by more than 50 persons, a sounder can be appropriate even for space intended for fewer than 50 persons, such as a library stack area.



### Locations that may not be suitable for directional **sounders** Under some circumstances, windows may be designated as an emergency means of escape. In schools and day care centers, they are designated as “windows for rescue,” intended to be used by firefighters to assist in evacuation, but not by the children on their own. In such locations, **Other Means of Egress Features**

**NFPA Definitions ICC Definitions** 

Common Path of Travel – The length of travel measured in the same manner as travel distance but terminating at the point where two separate and distinct routes of travel become available. Separate paths that merge also are common paths of travel. Common Path of Egress Travel – That portion of exit access which the occupants are required to traverse before two separate and distinctpaths of egress travel to two exits are available. Paths that merge are common paths of travel.

Dead-End Corridor – (commentary) A conditionwhere the corridor continues past an exit and creates a pocket into which an occupant might travel. Relatively short dead-ends are generally permitted. Dead-End Corridor – not defined; assumed tobe self-explanatory. A maximum dead-end corridor length of 20 feet is permitted.

Dead-End Corridorupdownupdown Enclosed Exit Stair

Figure 15. Dead-end corridor

Exit Common Path of Travel

X Dead-End

Exit

Figure 16. Common path of travel



### 11 sounders would serve no practical purpose. Windowsdesignated for escape also may be encountered in apartments and private residences, where sounders would not be appropriate.

Sounders are not appropriate under other circumstances.A stairway may stop before it reaches a point where it discharges to a place of safety, instead discharging back into the building at a point that can be involved in fire or filledE X I T P O I N T TM D I R E C T I O N A L S O U N D E R

with smoke. Elsewhere in a building, an exit door or stairway may not be accessible because there is an intervening door that might be locked. An exterior door that appears to lead to a place of safety actually leads to an outdoorenclosed space from which there is no escape. The building codes do not allow such doors or stairs to be considered as exits, and typically, there would be no exit signage in connection therewith. But mislabeling can occur, and changes are made to buildings without a complete review of the means of egress. It is possible for an exit sign to be improperly placed at a door or stairway that does not leadto safety, and placing directional sounders at such locations must be avoided. (It should be noted that both NFPA and ICC documents permit ground-level discharge from a stair back into the building under prescribed conditions. In these cases the stair is consider a viable exit and should be marked accordingly as an exit) Portable ladders, rope fire escapes and similar escape devices, according to appendix material in the NFPA LifeSafety Code, can be useful to facilitate escape from a burning building but may be unsuitable for use by aged or disabled people or by small children. Neither NFPA nor ICCrecognizes these as legitimate exits, and directional sounders should not be used to identify their location.

For new buildings, particularly, both NFPA and ICC state that access to an exit shall not pass through a high-hazardoccupancy, a kitchen, a storeroom or a closet. It is common, however, to find the second means of egress from a restaurant dining room to be through the kitchen, and there may be other circumstances where such “prohibited” means of egress are permitted. When such situations are encountered, the authority having jurisdiction should be contacted for the appropriateness of sounders at these apparent exit access paths.



### 12 

### GeneralGeneral guidance is provided in this section for directional sound installations for either new fire alarm systems or as enhancements to existing systems. Installation and maintenance instructions for the directional sounders provided by the manufacturer and NFPA 72 should be consulted for specific information related to mounting, device features, electrical wiring and appropriate settings.

Directional sound is a broadband, multi-frequency sound. A directional sounder should incorporate the capability to be set to multiple pulse patterns, each consisting of a period of directional sound interleaved with an optionalvoice message. The patterns are used to provide distinctive sound cues at an exit or along a route to the nearest exit and the voice messaging provides clear instructions to building occupants.

The pulse patterns can be set to signify increasing proximity to an exit, the fastest pulse being used at the exit. Otheraudible information can supplement the pulsing broadband sound as guidance. For example, each pulse pattern is capable of being supplemented with other audible cues such as voice messaging instructing occupants that they are approaching a stairway going up or down, or that they have reached an exit. Another direction given is that occupants are approaching an area of refuge, which should be distinctly marked.

The application or installation of directional sounders in buildings or structures requires an understanding of basic egress concepts and features. Key concepts and featuresthat are important considerations in developing and implementing an installation of directional sound devices have been reviewed and, again, are as follows:

• Exit access • Exit • Exit discharge

• R efuge area, area of refuge, or area of rescue assistance • Horizontal exit • Exit passageway • Dead-end corridor • Common path-of-travel • A fire escape when recognized as an exit The concepts used to position directional sounders differfrom the concepts applied to standard notification appliances (See System Sensor “Audible/Visible ApplianceGuide”). Generally, fire notification appliances in buildings, such as bells, horns and speakers, require placement at numerous locations in order to achieve the sound levels that can be heard and understood by occupants throughout all building areas. NFPA 72 would consider this a “public mode” application.

A symbol different from the traditional fire alarm devices should be used for directional sounders on installation floor plans. The following symbol is used in this guide and is suggested for general usage:

Figure 17. Directional sounder icon


### Type 1 (Basic) Installation A Type 1 installation calls for directional sound devices at the location of code-required exits and areas of refuge. The intent is to place a directional sound device in close proximity to the door of each exit or area of refuge as an audible cue for locating it in an emergency.

Examples of Type 1 installations are shown in Figures 18 through 20.

In a Type 1 installation of directional sounders, the concern is not for establishing an audible signal in all occupied building spaces. Rather, the focus is to provide sound cues to assist occupants in more easily locating the point of entry to an exit or area of refuge during an evacuation and under possibly smoky conditions. The key considerations for establishing a Type 1 installation are as follows:

• Using the guidance in the section “Locations for

Directional Sounders,” identify the doors leading to exits and areas of refuge. Also, identify areas where directional sounders should not be used.

• Determine the position of directional sounders based

on the recommended installation zones for doors, using the guidance in the following section “Positioning Directional Sounders on Wall and Ceiling Surfaces.” **Section 5** 

## Directional Sound **Installations**S Y S T E M S E N S O R

• Determine the ambient sound levels for the location of

each exit or area of refuge door. Specify the power setting that will result in a minimum 15 dBA sound level above ambient sound levels at ten feet from the device. Power settings resulting in a sound level in excess of 15 dBA above ambient are acceptable where greater sound level penetration is desired.

• Directional sounders located at exit doors are set to the

fastest pulse pattern and may the incorporate the voice message “Exit Here.” • Directional sounders located at stairwells are set to the fastest pulse pattern and may incorporate the voice messages “Stairs Up” or “Stairs Down”, depending on the orientation to ground level.

• D irectional sounders located at doors leading to exit

stairs that also have an area of refuge at or adjoining the landing are set to a fast pulse pattern, followed by the distinctive “area of refuge” supplemental indicator.

Enclosed Exit Stair Enclosed Exit Stairupdownupdown

Area of Refuge

Area of Refuge Sounder Set to ‘Fast’ Pulse Plus Refuge Tone to Mark Entrance to Exit Stair and Adjoining Area of Refuge

Sounder Set to Fast’ Pulse to Mark Exit Stair Sounder Set to ‘Slow’ Pulse Plus Refuge Tone to Mark Area of Refuge That is Not an Exit KEY

Exit Sign Shaded Quadrant Represents Visible Face Exit Sign With Designation of Directional Arrow

Directional Sounder
Full Height Walls
Partial Height Dividers

Figure 18. Directional sounders at exit stairways and areas of refuge in a Type 1 installation.

up up

down

down Common Path of TravelDead-EndDead-End In open-plan floors, Type 2 sounders should not be used for other than dead-ends or common path of travel conditions. Multiple sounders in the common egress route of an open floor plan would result in conflicting directional sound cues. Type 1 sounders may need to have the power setting increased for better penetration into the open floor space. KEY

Exit Sign Shaded Quadrant Represents Visible Face Exit Sign With Designation of Directional Arrow

Directional Sounder
Full Height Walls
Partial Height Dividers

Figure 19. Directional sounders in an open-plan building. 

### 13E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

• I n some cases, it may be beneficial to use additional

directional sounders prior to the location of the exit where intervening doors occur along the egress path, such as cross corridor doors which are self-closing or automatic closing. When such intervening doors significantly reduce the penetration of the directional sounder mounted at the exit along the egress pathway an additional sounder installed at the intervening doors will provide a sound cue for occupants seeking the exit located beyond the intervening doors (see Figure 20).

• A building’s emergency planning documents, including occupant training procedures, should be revised to reflect the meanings of the “slow” and “fast” pulse directional sounds and the supplemental signals.


### Type 2 (Enhanced) Installation A Type 2 installation is an enhanced Type 1 installation. In addition to the sounders needed for a Type 1 installation, it provides devices that give audible directional cues at key points along the means of egress, thereby guiding the person towards the exit or area of refuge. Locations to be considered for supplemental directional sounders in a Type 2 installation include the following:

• door from a room/area having a common path-oftravel,

• the outlet end of a dead-corridor,

• at points of multiple route choice where a directional

sound device is located leading in the direction of the nearest exit,

• at points along a route where the sounder at the exit

is not audible. In this case a directional sounder is installed to act as a locator of the egress route to the exit. Care must be taken in a Type 2 installation to guide the person in just one direction, generally the direction that leads to the closest exit. Situations that can lead a person into a circular route or into a dead-end must be avoided. A Type 2 installation requires additional analysis effort and design specification to properly implement directional sounders. The key considerations for establishing a Type 2 installation are as follows:

• Include all directional sounders necessary for a Type 1

installation.

• Use additional directional sounders where they will

enhance the ability of occupants to locate exits and the direction thereto. When locating a directional sounder at a point where the egress path turns or changes direction, preferably locate the sounder past the turn but no further than approximately 2 feet past the turn. It is also acceptable to locate the sounder just before the turn. See Figure 21 for the recommended zone for locating sounders at turns in the egress route such as a corridor.

• In some cases, it may be beneficial to use additional

directional sounders where intervening doors are located along an egress path such as cross corridor doors which are self-closing or automatic closing. When such intervening doors significantly reduce thepenetration of directional sound along the egress pathway an additional sounder installed at the intervening doors will provide a sound cue for occupants following the egress route that continues beyond the intervening doors. (See Figure 22.)



### 14 Fire Rating Based on Number of Stories

up downupdown

Corridor Set Directional Sounder to ‘Fast’ Pulse Pattern

Intervening Door

Additional sounder set to ‘Fast’ pulse to increase the directional sound penetration into the corridor once the intervening door closes. The sounder should be located on the corridor side of the door. Once the evacuees pass through the door they will begin to hear the sounder at the stairwell and proceed towards the actual exit.

Figure 20. Floor exit arrangement showing a corridor leading to an enclosed exit stair. Example indicating when directional sounders should be placed at an intervening door. 2 FT.

Direction of Travel to

the Nearest Exit

Center Line of Corridor Preferred Installation Zone

Acceptable Installation Zone

Direction of Travel to the Nearest Exit

Figure 21. Preferred and acceptable zones for location of directional sounders at a turn in the exit access route.S Y S T E M S E N S O R



### 15 Enclosed Exit Stair

up down

‘Fast’ Pulse ‘Medium 1’ Pulse

‘Medium 2’ Pulse

‘Slow’ Pulse KEY

Directional Sounder
Full Height Walls
Partial Height Dividers

Figure 23. Level 2 sounders in a long corridor, with slow to fast pulse patterns along the exit access route towards the exit. Enclosed Exit Stair

up down

‘Fast’ Pulse Location B ‘Medium 1’ Pulse

Location A ‘Medium 2’ Pulse

‘Slow’ Pulse For an intervening door close to a sounder, an additional sounder before the door may not be necessary. An appropriate alternative would be relocating the sounder from location B ahead of the door.

The intervening doors, when closed, are likely to reduce the sound penetration of the sounder at location A. Therefore, an additional sounder would be appropriate before the intervening doors. In this case the sounder mounted before the doors would be set to a ‘Medium 2’ pulse the same as the sounder at location A. Relocation Alternative

KEY

Directional Sounder
Full Height Walls

Figure 22. Building floor area served by enclosed exit stairs with intervening doors along egress route. Example indicating when additional directional sounders may be necessary at intervening doors. • Use increasing speed in pulse patterns in moving from

sounder locations most distant from the exit (slower pulse) to sounders nearer the exit (faster pulse). (See Figure 23.)E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

Enclosed Exit Stair

up down

‘Fast’ Pulse ‘Medium 1’ Pulse

‘Medium 2’ Pulse ‘Slow’ Pulse ‘Medium 2’ Pulse

Same Pulse OK If Not Same Route to Exit Not More Than Four Sounders Along Same Route to Exit

KEY

Directional Sounder
Full Height Walls

Figure 24. Sounders in a Type 2 installation in a long, complex exit access route.

Key Decision Point Key Decision PointRoute A Exit Exit

Exit Considerations for Occupant Load Balance: Although Route A is the shortest travel distance to an exit, Type 2 sounders are not recommended to be located along Route A due to the limited exit capacity. Where occupant balance issues may be present, it is recommended that directional sounders be limited to a Type 1 installation (exits only). Auditorium (400 Occupants) KEY

Exit Sign Shaded Quadrant Represents Visible Face Exit Sign With Designation of Directional Arrow

Directional Sounder
Full Height Walls

Figure 25. A Type 2 installation should not be used where supplemental sounders may not lead to the most appropriate exit. • Do not use more than four sounders in the route towards an exit. Only four pulse patterns are available (including that of the Type 1 sounder at the exit), and using two sounders with the same pulse patterns along the same route may cause confusion on the direction to the nearest exit. (See Figure 24.)

• Use a maximum separation

of 50 to 80 feet between sounders along the egresspath. In general, directional sound pressure will reduce by 6dB for every doubling of distance. In high sound absorbing locations the maximumseparation between directional sounders may needto be reduced. As indi

### 16 cated in Figure 28, sound pressure levels will drop to an ambient level at a distance of approximately 56 to 100 feet for sounders set to a sound pressure level of 15 to 21 dB above ambient (measured at 10 feet from device), respectively. As a general rule spacing sounders in the range of 50–80 feet apart will provide readily identifiable sound cues as occupants movethrough exit routes. Such spacing will result in occupants approaching the audible zone of the directional sounder within several steps after passing a previous sounder location.

• Use Type 2 sounders in rooms or spaces having an

open floor plan with a single means of egress that constitutes a common path of travel.

• A building’s emergency planning documents, including occupant training procedures, should be revised to reflect the meanings of the “slow” and “fast” pulse directional sounds and the supplemental signals.

A Type 2 installation is not always appropriate:

• Do not use a Type 2 installation for open floor plans

with multiple exits, where sounders will tend to conflict with each other.

• Do not use a Type 2 installation where occupant loads

and exit capacities are not reasonably balanced with travel distances to routes. (See Figure 25.)

Additional illustrations of Type 2 installations can be found in Figures 26 and 27.S Y S T E M S E N S O R



### 17 Enclosed Exit Stairupdown

Enclosed Exit Stairupdown Sounder Set to ‘Fast’ Pulse to Mark Exit Stair Sounder Set to Fast Pulse to Mark Exit Stair Corridor A

Corridor CCorridor B No directional sounder is needed in corridor with alternative directions of movement

Directional sounder is located in Corridor C in proximity of exit sign; intent is to provide sound cue outside Corridor B leading to direction of exit stair. Sounder set to ‘Medium 1’ pulse. Directional sounder is located in Corridor A in proximity of exit sign; intent is to provide sound cue outside Corridor B leading to direction of exit stair. Sounder set to ‘Medium 1’ pulse.

Suite with Common Path of Travel

Directional sounder is located to Provide sound cue of location of Suite egress door. Sounder set to ‘Medium 2’ pulse (optional if corridor Sounders are not audible). KEY

Exit Sign Shaded Quadrant Represents Visible Face
Exit Sign With Designation of Directional Arrow

Directional Sounder
Full Height Walls
Partial Height Dividers

Figure 26. Example of a Type 2 installation.

Key decision points should be identified as locations for directional sounders. The sounders are located on the side of the exit signs that is nearest an exit.

up down up

down Key egress decision point. For Type 2 installation locate directional sounder in direction of nearest exit.

Decision point with 4 egress rouite choices. Directional sounder is not recommended in these nearby corridor areas to avoid conflicting sound cues.

Key Decision Point

Key Decision Point Key Decision Point **A**

**C B**  Sounder placed at this location so that building occupants originating from points A, B, or C will follow the shortest path to an exit. KEY

Exit Sign Shaded Quadrant Represents Visible Face
Exit Sign With Designation of Directional Arrow

Directional Sounder
Full Height Walls

Figure 27. A Type 2 installation with multiple egress route decision points. Directional sounders are at exit stairways and at key egress route changes. Sounders in the corridor along the exit access route are needed if the directional sounders at the stairways are not audible.E X I T P O I N T TM D I R E C T I O N A L S O U N D E R



### Special Considerations for Dead-EndsFigures 29 and 30 illustrate common types of dead-end corridor conditions. In each case, when a directional sounder is used in a Type 2 installation, it should be located fully outside the dead-end corridor, such that a person will be directed out of the dead-end and towards the nearest exit. No sounder should be placed within the dead-end portionof the corridor as it may draw persons outside the deadend into the dead-end condition.

The shaded portions on the diagrams (Figures 29 and 30) give the preferred location of Type 2 sounders in each instance. To guide the occupants in the proper direction, the sounder should be placed into the access route to the nearest exit, past the dead-ends by not more than two feet. It can be either wall or ceiling-mounted. Once past this sounder, they should hear a more rapidly pulsed sounder in the direction of the exit.

The Type 2 sounder at the end of a dead-end corridor may be unnecessary if either the Type 1 sounder at the nearest exit or another Type 2 sounder in the exit access route is close by and readily audible at the far end of the dead-end. up down Dead-End 2’

Exit Stair Path to Alternate Exit

Path to Nearest Exit

* Not needed if sounder at stairway is audible at far end of dead-end. Locate Type 2 Directional Sounder Here* KEY

Directional Sounder
Full Height Walls

Figure 29. Directional sounder at single dead-end corridor. Dead-End Corridors No SounderNo SounderNo Sounder Path to Exit

2’
Type 2 Directional Sounder Location KEY

Directional Sounder
Full Height Walls

Figure 30. Directional sounder at multiple dead-end corridors. 

### Sound Pressure vs. Distance from Directional Sounder

–5

0 5 10 15 20 25

10 20 30 40 50 60 70 80 90 100 **Distance from Sounder (Feet) Sound Pressure above** **ambient (dB)**

Figure 28. Sound pressure of directional sound compared to ambient as a function of distance from the directional sounder. **Note:** I nitial sound pressure of directional sound set at 15dB, 18dB and 21dB greater than ambient at 10 feet.



### 18S Y S T E M S E N S O R

A directional sounder should be installed in close proximity to the location of a door or multiple doors that provide the initial entry point into or through the exit or area of refuge. In the case of smoke-proof towers or exit passageways that lead to an enclosed stair, the initial entry point is the first door encountered in the path into the smoke-proof tower or into the exit passageway. The following figures illustrate recommended zones for locating directional sounders on the wall or on a ceiling in cases where sufficient wall space for mounting a device is not available.

In the case of open floor plans, partial-height partitions can pose a sound absorbing obstruction to a directional sound device. The directional sounder shall be placed above the level of room dividers, preferably one to two feet higher.Figure 36 illustrates the desirable distance that a directional sounder should be installed above the highest partition, or divider, in the space.

Additional sounders may be needed at multiple arrays of multiple doors, based on sound pressure.

Floor Door Handle Height Ceiling Center Line of

Door

EXIT

12 in. 24 in. Hatch Area is Preferred Zone for Location of Directional Sounders

Hatch Area is Acceptable Zone for Location of Directional Sounders Example Locations for Directional Sounders Example Locations for Directional Sounders

Single Door

Figure 31. Sounder locations adjoining a single door. Floor Ceiling Center Line of

Door

EXIT

12 in. 24 in. Hatch Area is Recommended Zone for Location of Directional Sounders

Example Locations for Directional Sounders

Double Door

Figure 32. Sounder locations adjoining a double door.

Floor Ceiling

Center Line of Device 2 ft.

Where limited wall surfaces are available, a ceiling mount installation with directional sounder no more than 2 feet distance off face of door. Example Locations for Directional Sounders

Side View Floor Ceiling

Front View

Figure 33. Ceiling-mounted sounders. 

### 19 **Section 6** 

## Positioning Directional **Sounders on Wall and Ceiling Surfaces** E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

Where Directional Sounders Are Oriented toward a space with partial height dividers it is recommended that the directional sounder be above the top of tallest divider or partition.

24 in. Directional Sounder

Side View Floor Ceiling

Enclosed Exit Stair

60 in. Desirable

Figure 36. Sounder location above level of room dividers.

Floor Center Line of Door Array

EXIT 36 in.

24 In. Hatch Area Is Recommended Zone for Location of Directional Sounders Example Locations for Directional Sounders

Door Array – Recommended Location for Multiple Door Installation EXIT 36 in.

Figure 34. Sounder locations at multiple doors.

Wide Corridor Center Line of Door Array

36 in.

24 in. Hatch Area is Recommended Zone for Location of Directional Sounders Example Locations for Directional Sounders

Where egress approach is from one direction, the directional sounder should be located over both sets of doors encountered. 36 in.

EXIT

Example Separation of 6 ft. Separation May Be Larger

Wall Ends Direction Of Egress Approach Center Line of Door Array

36 in.

24 in. Hatch Area is Recommended Zone for Location of Directional Sounders Example Locations for Directional Sounders 36 in.

EXIT

Figure 35. Sounder location at single-directional approach to multiple doors.



### 20S Y S T E M S E N S O R

1. What is a directional sounder and how does it work? A directional sounder is a type of electronic signaling device that is installed as part of a building fire alarm system. When activated, it produces short bursts of broadband sound in a frequency range that is distinctive from the audible sounds of bells, horns, or voice speakers. The broadband sound pulses of directional sounders make use of our natural ability to localize the sound sources.

2. What does the term “Directional” refer to? The term “directional” refers to the unique characteristics of the sound that allow listeners to identify exactly where the sound is coming from. It does not in any way refer to the orientation or direction that the sound emanates from the sounder.

3. What is the advantage of adding directional sounders to a building’s emergency egress facilities? Directional sound technology offers a solution to improve the exit or escape situation for building occupants. To help occupants in finding their way to an exit, refuge area or other means of egress, directional sounders integrated with the fire alarm system provide additional auditory information that can assist or aid occupants in locating escape routes without conflicting with the traditional fire alarm system notification appliances such as bells, horns, or voice speakers. Directional sounders effectively serve as “audible exit signs.” They are installed at exits and at points in between as an additional cue for persons needing to find exits and areas of refuge in an emergency. Because sound travels around corners, directional sounders are not line-of-sight dependent, and their unique audibility is an assist for persons with visual impairments.

4. What activates and powers the directional sounders? Directional sounders are wired into and powered by thealarm notification circuits of the building’s fire alarm systems. Directional sounders are intended to operate simultaneously with the traditional fire alarm notification devices and to be wired as part of the fire alarm system notification circuits. There is no need to have a separate control panel for directional sounders.

5. Can directional sounders be installed as part of any fire alarm system?Directional sounders should be compatible with the manufacturer’s recommended power supplies for the fire alarm system in which the sounders are used. Additional power supplies may be needed to handle the added current draw of the directional sounders.

6. What is a Type 1 (basic) directional sounder installation? A Type 1 (basic) directional sounder installation is focused on providing directional sounders only at “exits” and “areas of refuge” as defined by building and fire codes.Such an installation typically includes a sounder at exterior exit doors, at doors leading into enclosed stairways or ramps, at the entrance to areas of refuge, at horizontal exit doors, and at other points defined as an “exit” or “area of Refuge” by applicable codes or standards.

7. What is a Type 2 (enhanced) directional sounder installation? A Type 2 installation is an enhanced Type 1 installation. In addition to the sounders needed for a Type 1 installation, it provides devices that give audible directional cues at key points along the means of egress, thereby guiding theperson to a nearby exit or area of refuge. In a Type 2 installation additional directional sounders can be used to mark the direction away from a dead-end corridor situation or identify the single means of egress from a room or space.

8. Are all installations either Type 1 or Type 2? Type 1 installation refers to an installation that locates directional sounders only at the exits. Type 2 installation refers to an installation that includes additional sounders throughout the egress pathways. There may be situationswhere a Type 1 installation is desired, however due to special situations, some additional sounders may be required. An example of a special situation might include the case where locating sounders only at the exit may not provide adequate sound penetration to reach the majority of the occupants. These installations may not be considered Type 2 installations since the objective isn’t to identify the entire egress pathway even though additional sounders are used.

9. How many directional sounders are needed in a building? Just as the numbers of traditional fire alarm signals are dictated by the size, configuration, noise levels and soundattenuation characteristics of a building, so are the numbers of directional sounders dependent on the characteristics of the building. It has to be taken into consideration whether a Type 1 or a Type 2 installation is being provided. Other considerations are the number of ground floor exits, the number of exit stairways and ramps, the complexity of exit access routes, the sound attenuation characteristics in the vicinity of sounder locations, ambient sound levels,and other parameters specific to each building. As a general guide, directional sounders are sufficiently audible at distances of 50 to 100 feet.

10. Are directional sounders UL listed? In the case of a directional sounder the applicable test standard is UL 464, Audible Signal Appliances. Per this standard the System Sensor directional sounder device is listed as a “supplemental notification appliance.”

11. Are there some locations that are not suitable for directional sounders? Directional sounders should not be placed at means of escape that are not recognized as “exits” by codes and standards, such as emergency rescue windows. Also, directional sounders should be avoided if they might create confusion on the nearest or best exit to use. In large, open areas, there may be multiple exits, but multiple directional sounders can cause interference with each other.



### 21 **Section 7** 

## Frequently Asked **Questions**E X I T P O I N T TM D I R E C T I O N A L S O U N D E R

ADA The American With Disabilities Act. An act of Congress signed into law in 1990 intended to ensure civil rights for people with disabilities.

ADAAG The Americans With Disabilities Act Accessibility Guidelines. Developed as “rules” for accessible design. ADAAG includes both scoping and technical requirements for building design and construction.

Area of refuge A space within a building, separated from the remainder of the building by fire-resistive construction, that serves as a relatively safe staging area for people who cannot easily use stairways while awaiting assistance for evacuation. Also known as “area of rescue assistance.”

Average ambient sound The average sound level measured in a given area over the period of occupancy.

Bandwidth The frequency range of an audible appliance, measured in cycles per second, or Hertz (Hz). Audible fire alarm appliances typically are in the 3000 Hz range, while directional sounders cover most of the spectrum capable of being heard by the human ear (approximately from 20 to 20,000 Hz).

Corridor dead-end That portion of a corridor that has only a single direction of travel towards an exit. Exit That portion of a means of egress that is separated from the building to afford a protected path of travel to the exterior. Typically, the exit starts at an exterior door,a door into an enclosed stairway, or at doors of an horizontal exit.

Exit access That portion of a means from egress leading from any occupied portion of a building to an exit.

FHA The Fair Housing Amendment Act is federal legislation promulgated by the United States Department of Housing and Urban Development. The FHA provides for fair housing protection against discrimination on the basis of family status or persons with disabilities.

FHAG The Fair Housing Accessibility Guidelines. The FHAG includes both scoping and technical requirements for a broad category of residential construction.

ICC International Code Council, Inc. Publishers of the International Building Code, International Fire Code and other, related documents.

NFPA National Fire Protection Association. Publishers of fire safety codes and standards, like the Life Safety Code and National Fire Alarm Code, and NFPA 5000, a model building code.

Traditional fire alarm signal Audible and visual fire and evacuation notification appliances of a fire alarm system, such as horns, bells, speakers, and strobes.



### 22 **Section 8** 

## GlossaryS Y S T E M S E N S O R

5. Blauert, J. (1997) Spatial Hearing, Cambridge, MA: MIT Press.

6. Withington, D. J., Localisable Alarms, extract from N.A. Stanton and J. Edworthy (eds), Human Factors in Auditory Warnings, Ashgate Publishing Ltd. (1999).

7. Withington, D. J. 2002b, Life Saving Applications of Directional Sound, in M. Schreckenberg and S. D. Sharma (eds), Pedestrian and Evacuation Dynamics (Berlin/New York: Springer).

8. National Fire Protection Association, National Fire Alarm Code, Quincy, MA: 2002, 137.

9. National Fire Protection Association, op. cit., 138. 1. Sime, Jonathan, “Movement Toward the Familiar Person and Place Affiliation in a Fire Entrapment Setting, “ Environment and Behaviour 17:6 (1985) 697-724.

2. McClintock, T., et al, “A Behavioral Solution to the Learned Irrelevance of Emergency Exit Signage,” 2d International Symposium on Human Behavior in Fire, March 26-28, 2001, Boston, MIT InterScience Communications, 23-33.

3. SFPE Engineering Guide, Human Behavior in Fire, Society of Fire Protection Engineers, Bethesda, Maryland, 2003.

4. F.L. Wightman and D.J. Kistler, Sound Localization, in W.A. Yost, A. N. Popper and R.R. Fay (eds), Human Psychophysics, New York: Springer-Verlag (1993). 

## References

23E X I T P O I N T TM D I R E C T I O N A L S O U N D E R



### 24 

## List of Illustrations
Figure 1. Interaural time and intensity differences of sound.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 2. Examples of frequency dependent attenuation for sources

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 3. Typical ambient sound levels

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 4. Frequency response of traditional fire alarm signals versus directional sounder

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 5. Exit access starts from any normally occupied point on a floor.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 6. Different types of exits illustrated.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 7. Fire-rated enclosed stair.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 8. Smokeproof tower.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 9. Smokeproof tower, mechanically vented.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 10. Building floor area served by enclosed exit stairs and horizontal exit fire barrier wall.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 11. Illustration of a horizontal exit using a bridge between two buildings.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 12. Floor exit arrangement showing a fire rated exit passageway.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 13. Areas of refuge at stairways.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 14. Area of refuge at elevator lobby, serving an accessible means of egress elevator.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 15. Dead-end corridor.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 16. Common path of travel

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 17. Directional sounder icon

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 18. Directional sounders at exit stairways and areas of refuge in a Type 1 installation.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 19. Directional sounders in an open-plan building.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 20. Floor exit arrangement showing a corridor and intervening door scenario.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 21. Preferred and acceptable zones for location of directional sounders

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 22. Building floor area served by enclosed exit stairs and horizontal exit fire barrier wall

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 23. Level 2 sounders in a long corridor.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 24. Sounders in a Type 2 installation in a long, complex exit access route

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 25. A Type 2 installation should not be used where supplemental sounders may not lead to the most appropriate exit

. . . . . . . 16 Figure 26. Example of a Type 2 installation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Figure 27. A Type 2 installation with multiple egress route decision points.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Figure 28. Sound pressure of directional sound compared to ambient

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 29. Directional sounder at single dead-end corridor.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 30. Directional sounder at multiple dead-end corridors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 31. Sounder locations adjoining a single door

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 32. Sounder locations adjoining a double door

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 33. Ceiling-mounted sounders

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 34. Sounder locations at multiple doors.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Figure 35. Sounder location at single-directional approach to multiple doors.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Figure 36. Sounder location above level of room dividers.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20©2007 System Sensor. The company reserves the right to change specifications at any time. A05-1048-001 • 3/07 • #1786