ABS Crew Habitability

8/12/2019 ABS Crew Habitability

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by improving productivity and safety, as well as reducing the

potential for human error. If habitability is defined as the

quality of the spaces where personnel work, sleep, rest,recreate, and dine along with the associated ambient

environmental conditions in those spaces, then it is logical that

these factors can affect the quality of life of those aboard

offshore installations. It is the contention of the authors of this

paper, that applying human factors habitability criteria willindeed impact the effectiveness and safety of personnel, as

well as enhance their \ comfort, and encourage crew retention.While information relating to habitability exists in a

variety of sources, what has been lacking is an internationally

accepted single-source of habitability criteria. Existing

guidance includes numerous guides, codes, and standards,which focus on particular aspects of habitability. Some of

these sources are particular to certain segments of the offshore

industry, (e.g., United States Code of Federal Regulations (US

CFR), or the Norwegian Oil Industry and the Federation of

Norwegian Engineering Industries (NORSOK) criteria)3,4.Some sources have international applicability such as certain

International Labor Organizations (ILO) Conventions5 andInternational Organization for Standardization (ISO) standards

but these are limited in application. Others, while still in

existence, are no longer specifically required (e.g., United

Kingdom's Department of Energy (UK DOE) guidance)6.

Upon a thorough review of such habitabilitydocumentation, conflicts were found between different

requirements within and between documents or in some cases,

criteria that could not be reasonably applied or assessed.

Another troublesome aspect with regard to the habitabilityliterature is that the criteria within some standards, codes, or

guides are aimed only at maintaining minimal health levels,

and do not provide data with regards to necessary minimumsfor crew member task performance or comfort. To be

effective, habitability criteria should specify conditions thatwill provide restful sleep, less physical wear and tear, and

promote overall health and welfare of crew members.

Using the existing documents mentioned above, togetherwith research related to human efficiency and comfort, ABS

carefully selected habitability criteria and measurement

methodologies. This information was then organized into theABS Guide for Crew Habitability on Offshore Installations.

The Guide not only provides industry with a single source for

habitability criteria and measurement methodologies, but isalso allows ABS clients to obtain an optional class notation of

HABor HAB+for crew habitability.The ABS Guide addresses two major aspects of

installation design: accommodations and the ambientenvironment. Accommodations criteria are provided for livingand some work areas. Both criteria and measurement

methodologies are presented for ambient environmental

concerns. The ambient environment sections of the Guide are

concerned with conditions that crew members may not be

conscious of or be primarily concerned with, but are factorsthat can greatly influence their performance and their

perception of comfort and well-being.

The ABS Guide provides prescriptive requirements for

accommodations concerns and functional requirements andassessment techniques with regard to ambient environmental

factors. It specifies what the end result of the design,

construction, and operations should accomplish rather than

describing the design process by which the criteria can be

achieved. The various measurement methodologies have beenstreamlined and provide a practical means to ensure that a

representative sample of data can be obtained during on-board

verification testing.

The following sections of this paper will describe the

accommodations and ambient environment topic areasincluded within the ABS Guide and the results of field-test

validation exercises.

AccommodationsOne of the more directly noticeable factors for impacting

human perception of habitability is accommodations designAccommodations spaces, where the installation's design can

have a favorable impact on such perceptions, include those

areas where workers rest, recreate, relax, and dine. Other

accommodations spaces, which will affect crew member

quality of life, and potentially their health and safety, are thesanitary spaces, food service areas, and access/egress design.

For crew members, the quality of accommodations spaceswill not only affect their job performance but can also

influence their comfort. Good crew accommodations should

not be aimed at merely maintaining minimum health levels bu

be targeted to support reliable crew performance and comfort

The accommodations, though perhaps not the primaryinfluence, can also affect a crew members decision with

regard to serving or continuing to serve aboard an installation.

To provide applicable criteria for accommodations

evaluation, ABS personnel reviewed over 40 guides, codesand standards relating to habitability. Some sources had

international applicability (e.g., ISO standards), others were

particular to certain countries (e.g., US CFR), others wereaimed at certain segments of the offshore industry (e.g.

NORSOK) and some sources were extracted from humanfactors literature.

Originally a set of almost 1000 candidate criteria wereidentified. After redundancies were culled, conflicting criteria

were resolved and unquantifiable criteria were dropped, the

criteria set was reduced to approximately 400. Then the

criteria was categorized as follows:Access/Egress Berthing

Sanitary Spaces Office

Food Recreational FacilitiesLaundry Medical

Each category of criteria is presented as a checklist

Within each category of criteria, logical subcategories were

created in order to make the checklists easy to use. Toleranceranges were often given for a particular criterion and all valueswere given in both metric and English units.

Ambient Environmental ConditionsVibration. Working and/or living aboard offshoreinstallations can subject workers to human whole-body

vibration. These vibrations will be transmitted to crew

members via the installation's structure. There are manyvarieties of potential vibration sources including wave and

wind actions, drilling operations, machinery operations, or in

the case of offshore vessels, ship motions.


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Prolonged vibration to the human body can result in a

variety of problems. Research shows that mechanical vibration

may interfere with the crews work quality, productivity, andsafety. Vibrations resulting from wind, waves, or vessel

operations result in motions that are more likely to affect a

crew member's sense of comfort and can cause motion

sickness. For this reason, the ABS Guide has specified

vibration limits for the frequency ranges that relate to bothmechanical vibration and installation motions.

To determine the limits and methodologies to includewithin the ABS Guide, numerous international and national

standards were thoroughly reviewed. Based on our

assessment, the British Standard 6841 (1987), Measurement

and Evaluation of Human Exposure to Whole-Body

Mechanical Vibration and Repeated Shock7,was chosen as the

basis for vibration evaluation. Using this methodology and

human performance vibration response data, limits were

chosen that would support crew member performance on

visual and manual tasks, as well as increase the potential forcrew comfort8. While the ABS Guide does not require an

installation's vibration levels be assessed in the range relatingto the frequency bands where humans show sensitivity (0.1 -

0.5 hertz) to motion sickness, the ABS Guide provides such

information for the industry's benefit.

Noise. Another factor that can significantly influence a crewmembers task performance is noise. Prolonged exposure to

noise can interfere with speech communications, impair

concentration, and result in a sensation of annoyance.

Unexpected intermittent noises are more disruptive thancontinuous noise, and sudden or impact noise may induce

physiological reactions and emotional changes. Limiting noise

is crucial for providing a supportive working environment forcrew members. While international and national rules exist

with regard to hearing conservation, the ABS Guide providesnoise criteria aimed at supporting crew member task and

communications needs. To accomplish this, appropriate noise

limits were set for each type of space that would normally beexpected to exist on an offshore installation. The limits were

determined by considering the following points for

each space:

What activities typically take place in the space?

What is the frequency of occupation of the space(unmanned, intermittently manned, or continuously

manned)?

What are the communication requirements in the space?

What noise levels do people typically expect in the space?

For the noise measurement methodology, the ABS Guide

adopted the techniques and conditions outlined in ISO-2923,

AcousticsMeasurement of Noise On Board Vessels9. Meeting

the ABS criteria allows an installation to provide anenvironment where crew members should find tasks that

require communication or concentration easier to accomplish.

It is also believed that the majority of workers will judgethe noise levels (stated in the ABS Guide) to be appropriate

for the activities they may wish to engage in during their time

aboard the installation whether it be working their shift or

relaxing during time off from work.

Indoor Climate. Indoor climate is another factor that can

influence crew member performance. Generally, inappropriate

indoor climate levels are only perceived when conditionschange or become extreme. The reason for this is that the

human body has the capacity to thermo-regulate itself in

various environments by producing or losing heat to maintain

a comfortable core temperature level. However, this capacity

has limits. As a result, it is important to regulate and controlindoor conditions such that people do not become aware of

noticeable changes (ANSI/ASHRAE 55a-1995)10.Temperature is the condition that most people associate

with climatic comfort, however, other influential factors

include humidity levels, temperature gradients, and air

velocities. As a result, the ABS Guide provides criteria foreach of these factors. Limits were chosen to facilitate crew

member task performance and comfort. The measuremen

methodology specified in the ABS Guide is ANSI/ASHRAE

55-a-199510.

The ABS Guide sets forth clear criteria for selectingmeasurement locations for indoor climate. By meeting the

criteria in the ABS Guide, the installation owner or operatorcan create a climate that is satisfactory to most crew members

and supportive of task performance.

Lighting. For most activities, whether work-related or

recreational, vision is a main sensory channel for receivinginformation. Proper illumination is therefore a critical design

element11,12,13.

Lighting is a powerful tool for creating an atmosphere

with regards to the desired activity levels within a spaceProper use of lighting can encourage movement or facilitate

sleep. At a more basic level, sufficient lighting is required to

facilitate reading and inspection tasks, to permit the viewingof displays, as well as to facilitate emergency and escape

activities. Improper use of lighting may result in visuadiscomfort that can affect crew member task performance

Visual discomfort can reduce concentration, the ability to read

or see, or even result in confusion. Human errors can resulfrom visual discomfort by making visual tasks difficult

leading the crew to under and overestimation of distances, or

to simply misread a chart or a display.Considering the potential impact that inappropriate

lighting levels can have with regards to crew members, ABS

personnel decided that it was necessary to include lightingcriteria as a part of the comprehensive set of habitability

criteria.

Appropriate lighting levels were chosen for each type of

space likely to be found aboard an installation. Minimum andpreferred levels were selected based on the type of task oractivity that was likely to occur within a space. As a result

different lighting levels were chosen for a control room versus

a sick bay/medical facility. The measurement methodology

chosen for lighting was IESNA-RP 12, RecommendedPractice for Marine Lighting14.

It should be noted that the ABS Guide does not specify

emergency lighting levels or require such measurements betaken. This was decided based on the fact that emergency

lighting is addressed in IMO Resolution A.752 (18)15, the

International Convention for the Safety of Life at Sea

(SOLAS)16and during normal classification processes.


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By using the ABS Guide's lighting criteria, along with

IMO, SOLAS, Class, or national requirements, the installation

operator or owner can ensure that an appropriate lightingenvironment is provided. While the ABS Guide only requires

adherence to the minimum levels, it also provides preferred

lighting levels to allow the installation operator or owner to

further enhance lighting aboard their installation.

ABS Optional Habitability NotationInstallation owners, construction yards, or shipyards that areclassing with ABS can request to be awarded a Habitability

notation. At the owners or yard's request, an installation

complying with the accommodations and the ambient

environmental criteria stated in the ABS Guide to Crew

Habitability on Offshore Installations shall be assigned a

notation of HAB. An installation complying with all of themore stringent habitability criteria with respect to whole-body

vibration and indoor climate shall be distinguished in the ABS

Recordby the notation HAB+. A summary of the differencesbetween each of the notations is given below.

Ambient Environment

NotationAccommo

-dations

Vibration Noise Indoor Climate Lighting

HAB

Must meet

performance-

basedvibrationcriteria

The criteriaprovides for a

set

temperaturewithin limits

HAB+

Nodifference

between

HABand

HAB+ Must meetcomfort-basedvibration level

criteria

No

differencebetween

HABand

HAB+The criteria

provides for

adjustabilityto suit comfort

No

differencebetween

HABand

HAB+

Field-Testing ValidationsSince the publication of the ABS Guide for Crew Habitabilityon Offshore Installations in 2002 and ABS Guide for Crew

Habitability on Ships in 2001, ABS has been performing

validation exercises related to the ambient environmentalcriteria contained in these Guides. Data collection efforts

started in March of 2002 and will continue through the end of

2003. During this time, data has been obtained from multiple

sources including offshore installations, commercial vessels,

and crew member spaces of passenger ferries and cruise ships.The objectives of this testing effort were to:

Validate the ambient environmental criteria contained

within the ABS Guides

Evaluate the measurement procedures and methods asexpressed in the ABS Guides

Identify any difficulties in with the criteria themselves orproblems with executing the measurement procedures. If

difficulties were found, improvements for future revisions

of the ABS Guides would be recommended.

Ambient environmental measurements were taken and are

being taken at every opportunity. The testing methodologiesand required testing conditions as described in the ABS

Guides were followed to the extent possible given the

opportunities provided. Unfortunately, ABS has not been able

to measure every ambient environmental aspect during eachtesting opportunity. As a result more lighting, noise, and

indoor climate measurements have been taken than whole-

body vibration measurements. The following summarizes the

results of field-testing.

Vibration - Testing Results. Vibration has been measured

during an extended ship voyage. With few exceptions

vibration levels measured in manned crew spaces whileunderway were within the Guides limits. The results of the

testing matched the subjective judgment of the vesselsCaptain and crew.

For the vibration test, the measurement procedures

methodologies, and required testing conditions were followedwith the exception of maintaining a heading dead or 90 dead

into the swell. Additional vibration testing is scheduled on

offshore installations.

Noise - Testing Results. In general, the ABS stated noiselimits have been found to be appropriate for the various spaces

that have been tested. Where deviations from the ABS Guides

noise criteria have been noted, the average variance has beenapproximately five decibels, with few variances exceeding 10

decibels.

With regard to human hearing, noise levels with adifference in intensity of five decibels are considered just

noticeable, however the increase could be enough to disrupt

sleeping and resting activities, but is not likely to interfere

with voice communications. Many of the variances from

criteria were observed to result from HVAC systems.

Variances of greater than five decibels constitute a clearlynoticeable difference in terms of subjective response to noise

that can interfer with activities such as voice communications

and sleeping. Comments from crew members supported this

view. Crew members reported having to speak louder to beheard, and reported wearing hearing protection (e.g., ear

plugs) while sleeping.Noise levels exceeding the Guides criteria by ten or more

decibels is likely to significantly impact voice

communications and the audibility of alarms, as well as to

interfere with rest and recreation activities.

The ABS criteria themselves appear appropriate for theactivities taking place. Where deviations were found during

testing is was suggested that the owner/operator should

determine if cost-effective means could be used to reduce thenoise levels.

Indoor Climate - Testing Results. Generally, temperatureand humidity levels were found be within the limits specified

by the ABS Guide. Humidity was an aspect of indoor climate

frequently reported as a source of discomfort. Many spaces

measured had relatively low levels of humidity (30 40 %)

though the values are within the limits of the Guide.

Lighting - Testing Results.To date, lighting has proved to be

the environmental variable where the most variances from

Guide requirements have been observed. Most of thesevariances genuinely result from inadequate lighting.

Some of the more significant variances included muster

stations, food preparation areas, and on-deck areas where


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inspection and display reading tasks are performed at night. In

such cases, correction of the variances was believed to be

possible through changing bulbs providing the lighting or byadding more lighting fixtures. For the less significant

variances, the addition of task lighting would most likely bring

lighting levels up to meet the Guides criteria.

Performance of The ABS GuidePerforming on-board environmental measurements related to

ambient environmental criteria in the ABS Guide has beenhelpful in its validation. The criteria in the ABS Guides are

based on sound research, however, it is necessary that the

feasibility of the criteria be assessed under the conditions of

working offshore installations and vessels. While the actualtesting results are important, crew members comments, and

ABS test personnel observations have also helped to identify

where the Guide might be improved.

Observations made regarding the performance of the

measurement methodologies and criteria within the Guide areprovided below:Vibration. Vibration measurements have been performedunder the prescribed test conditions with the results showing

that the maximum vibration levels imposed by the Guide are

achievable. Further testing is needed to verify the criteria are

appropriate for all types of vessels and installations.Noise. Most noise limits stated in the ABS Guide were foundto be reasonable and achievable, with few variances from the

ABS Guides criteria being observed. Variances were noted in

spaces such as dining spaces, gymnasiums, and recreational

spaces. In many of these instances the noise level, asmeasured, was found to be acceptable in the subjective

judgments of crew members and ABS testing personnel.

Given the generally small extent of variance of criteria toobserved noise levels, the methods and criteria in the guide

seem to be appropriate.Indoor Climate. Generally, the measured temperature and

humidity levels meet the criteria in the guide. Comments from

crew members and observations of ABS testing personnelabout discomfort associated with low humidity levels, suggest

that the criteria related to acceptable humidity levels be

reexamined. All other ABS criteria related to indoor climateappear appropriate at this time.Lighting.Numerous surveys of lighting have been performed

and many variances from the Guides criteria have been noted.Most of the variances were clearly due to inadequate

illumination. In observations where the lighting levels were

marginal, the subjective judgments of crew members and ABS

testing personnel was that the measured lighting levels wereadequate. That those marginal cases were generally deemedadequate, indicates that the acceptability thresholds for

lighting expressed in the Guide are appropriate.

Measurement Methodologies. The measurement methods

within the guide performed well, and no modifications havebeen deemed to be needed.

Discussion And ConclusionGiven the current set of measurement data, and experience

implementing the measurement methods provided by the

Guide, it can be stated that the Guide performs very well for

its intended purpose.

In all cases, the measurement methods successfully

guided the collection and documentation of the appropriate

data. When these measurements are compared to theenvironmental criteria within the Guide, a tendency is easily

discerned: the physical measurements are approximately

coincident with the criteria values. This tendency is true

regardless of the physical aspect of the environment that has

been surveyed. Further, subjective observations support theview that those environmental acceptance criteria are

consistent with perceived comfort.From the observations above, the following can be

asserted:

The methodologies within the Guide are appropriate.

The environmental criteria are appropriate to achieve

human comfort.

Since the measured and observed environmentalconditions generally meet guide criteria, and the

prevailing opinion that comfort is achieved in those

environments, then it can be asserted that the specific

criteria in the guide are both effective and achievable inoffshore structures.

In other words, the engineering demands imposed by the

Guide do not seem excessive or unreasonable.

References1. American Bureau of Shipping (2002) ABS Guide to Crew

Habitability on Offshore Installations. ABS: Houston, Texas.2. Robertson, N.L. Starting Right: Sable Offshore Energy Project'

HFE Program (OTC 10877). Paper presented at the 1999Offshore Technology Conference, Houston, Texas

May 3-6, 1999.3. Norwegian Oil Industry Association and The Federation o

Norwegian Engineering Industries (NORSOK). (1996)

Common requirements, architectural components & equipmen(C-CR-002). Oslo: Author.

4. Norwegian Oil Industry Association and The Federation o

Norwegian Engineering Industries (NORSOK). (1997)Working environment (S-002). Oslo: Author.

5. International Labor Office. (1998). Maritime labor conventionand recommendations (4th ed.). Geneva: Author.

6. UK Department of Energy. Offshore Installations: Guidance onDesign, Construction and Certification (4

th edition). London

HMSO, 1990.7. British Standards Institution. (1987). Guide to measurement and

evaluation of human exposure to whole-body mechanicavibration and repeated shock (BS 6841: 1987). London: Author.

8. Griffin M. J. (1990). Handbook of human vibration. LondonAcademic Press.

9. International Organization for Standardization. (1996)

Acoustics Measurement of noise shipboard vessels (ISO 29231996). Geneva: Author.

10. American National Standards Institute. (1995). Thermaenvironmental conditions for human occupancy

(ANSI/ASHRAE 55a-1995). Atlanta: The American Society oHeating, Refrigerating, and Air-Conditioning Engineers, Inc.

11. Sanders, M.S., & McCormick, E.J. (1993). Human factors inengineering and design (7th ed.). New York: McGraw-Hill, Inc.

12. Woodson, W.E., Tillman, B., and Tillman, P. (1992). Humanfactors design handbook: Information and guidelines for the

design of systems, facilities, equipment, and products for humanuse (2nd ed.). New York: McGraw-Hill, Inc.


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13. British Standards Institution. (1995). Ergonomics of the thermalenvironment Principles and application of relevantInternational Standards (BS ISO 11399: 1995). London: Author.

14. Illuminating Engineering Society of North America. (1997).

Recommended practice for marine lighting (IESNA RP-12-97).New York: Author.

15. IMO Resolution A.752 (18), Guidelines for the Evaluation andTesting and Application of Low-Location Lighting on Passenger

Ships, November 1993.16. IMO, International Convention for the Safety of Life at

Sea (SOLAS).

Documents

ABS Crew Habitability