A case study investigation of the indoor environmental noise in four urban South African hospitals

Abstract

The field of acoustics in architecture is often neglected by spatial designers, being thought of as a specialist field only applicable for complex acoustic requirements. However, research shows that environmental noise has a significant effect on humans and thus should be considered in all indoor environment design, no matter the occupancy type. This case study research seeks to investigate acoustics within healthcare facilities, specifically in multi-bed general wards in four urban South African hospitals. Sound can have either an auditory or non-auditory effect on humans, meaning it can either cause hearing damage or result in subjective responses that affect performance and physiology. This is an important consideration in a healthcare setting as the principle of ‘do no harm’ should apply to clinical treatment as well as the clinical environment. Noise control in healthcare environments can be a challenge since most of the surface finishes are hard and smooth, making them easily cleanable but also acoustically reflective, which can potentially cause spaces to become very noisy. Guidelines have been developed internationally by the World Health Organisation (WHO) (Berglund, Lindvall & Schwela 1999) and nationally by the South African Bureau of Standards (South Africa 2008) defining noise limits in various contexts, including hospitals. Prior research in the area of evidence-based design has shown that a quiet environment is conducive to patient healing and has been shown to improve staff work performance and decrease stress, irritation and tiredness. However, numerous international studies have revealed that few hospitals world-wide, if any, comply with the WHO guidelines (Busch-Vishniac, West, Barnhill, Hunter, Orellana & Chivukula 2005), highlighting the challenge that exists in designing quiet hospital environments. Since the research in this regard is extremely limited in the South African context, the goal of this research is to investigate the acoustic environment of a selection of South African hospitals to determine whether there is a likely need to design hospitals for improved noise control. This research project was designed as a multiple case study with the purpose of identifying possible areas for future research. The existing acoustic conditions in a ward of each of four urban hospitals were assessed in terms of sound levels, user opinions and architecture. The research objective was firstly to establish whether the selected hospitals are too noisy according to national and international guidelines, and then to determine the cause of the noise, whether it is actual or perceived noise, and whether design factors have an influence on the noise. Environmental noise was assessed by means of a Class 1 integrating sound level meter, questionnaires and direct observation. It was found that the average sound levels exceeded both local and international guidelines. In spite of this, however, the overall opinion of users was that noise levels were not disturbing. A combined assessment of the data revealed that layout may influence the acoustic environment and is worthy of more extensive research, particularly with regard to the difference between patient and staff member perceptions of sound. Other recommendations pertain to the establishment of design noise guidelines that address occupied noise levels in hospital wards, which would require an extensive study of human responses to noise exposure as well as factors that can either influence the response to noise or the noise level.