ABS guide focuses on habitat noise, vibration, other factors
As the petroleum industry moves into new frontiers and remote environments, operators and service companies need to re-examine the health, safety, and comfort levels of crews aboard offshore installations, said Denise B. McCafferty, Man-ager of Safety Assessment and Human Factors for ABS. To address this, ABS released the "Crew Habitability Guide," which provides criteria for living and working conditions that improve productivity, morale, and overall safety.
The guide provides the industry with a single-source document addressing crew performance and quality of life aboard offshore installations, including mobile offshore drilling units, fixed facilities, and floating installations, said McCafferty. She said the design of accommodations can influence performance.
Habitability
The ABS guide defines habitability as the acceptable condition of an offshore installation in terms of noise, vibration, indoor climate, and lighting, as well as accommodation design. ABS has identified critical performance issues and select appropriate accommodation design criteria, as well as defined limits for ambient environmental factors. The guide provides quantifiable assessment criteria and describes the measurement methodology for obtaining a habitability (HAB or HAB+) notation or certification. These assessments are voluntary and optional and can assist offshore operators in improving crew member performance and their living and working conditions.
For the HAB level, the guide focuses on the five categories of habitability criteria that can affect crew task performance. The HAB+ level addresses the same habitability categories but calls out more stringent vibration and indoor climate criteria aimed at increasing crew comfort. ABS-classed installations that meet the specified criteria will be awarded the appropriate notation. For non-ABS classed installations, certification to either HAB or HAB+ is offered.
Accommodation design
Technological advances have resulted in reduced staffing of facilities, increases in the complexity of on-board systems and greater remote control of equipment and/or platforms. Therefore, those crew members remaining aboard distant installations must maintain enhanced levels of mental and physical fitness to ensure the safety of the process, the equipment and fellow crew members.
"Crew members may be required to live away from home for extended periods of time under unique and sometimes harsh conditions. Remaining alert and readily able to address any situation is an important part of safety, and these factors can be influenced by habitability," said McCafferty.
Habitability issues extend to both living and working conditions. Criteria are provided for work spaces such as control rooms, bridges and machinery spaces. For accommodation spaces, habitability criteria are provided for offices, workshops, mess rooms, cabins, hospitals/sick bays, recreation rooms, laundries, and storerooms. The accommodation criteria for a HAB or HAB+ notation or certification are the same.
Whole-body vibration
Aboard most installations, the crew is subjected to low-frequency motions from installation movement or single impulse shock loads as well as to high-frequency mechanical vibrations. For the basic HAB level, criteria for vibration occurring in the accommodation are aimed at limiting potential interference with work tasks. The more stringent vibration criteria for the HAB+ level are aimed at improving crew comfort. HAB+ is the crew's ability to use a space for its intended purpose with minimal interference or annoyance from vibration. "This approach focuses upon the individual human being as the receiver of low-frequency and high-frequency vibration - a significant departure from standards that concentrate solely upon measuring high-frequency mechanical vibration from machinery," said McCafferty.
Noise conditions
Numerous studies have established the effects of noise upon speech communication, hearing loss, sleep, and annoyance. Noise levels can have an enormous impact upon physiology, psychology, and health, and the guide specifies maximum noise levels based on a time-weighted average in crew accommodation spaces and working areas, navigation and control spaces, service spaces, operating spaces, and maintenance areas. The noise criteria for the HAB and the HAB+ levels are the same.
Indoor climate
The criteria of the guide addresses climatically controlled crew living and working spaces. Factors including air temperature, air velocity, humidity and personal issues, such as physical activity and clothing, influence comfort. The HAB criteria for indoor climate provide for a pre-set return air temperature maintained by a temperature controller for each zone. The HAB level does not make provisions for allowing adjustments to suit personal preferences for temperature, circulation, and dehumidification within each specific space.
"Because there are individual differences between people's temperature sensitivity and perception of comfort, the more stringent HAB+ level is aimed at enhancing crew comfort by making provisions for adjusting indoor climate to suit personal needs within specific spaces," said McCafferty.
Lighting
The lighting of crew spaces must facilitate visual task performance and safe crew movement. Important considerations include task length, visual fatigue, glare, reflections or shadows and the age and visual acuity of the observer. "While sufficient lighting is essential for both indoor and outdoor areas on an installation, the controversy with lighting arises in determining 'sufficient' illumination," said McCafferty.
The guide defines acceptable lighting levels for crew accommodation spaces, navigation and control spaces, service spaces, operating and maintenance spaces and drilling compartments, based on the likely tasks. Criteria are also given for spaces that use red, low-level white, or blue illuminence for nighttime operations. The lighting criteria are the same for the HAB and HAB+ levels.
