Acoustics

BS ISO 22955:2021 pdf free.Acoustics一Acoustic quality of open office spaces.
An open-plan space is often promoted as a flexible space, a space for communication (visual and oral) and activity associated with a job, and for discussion, where information flows freely. However, not all the speech generated in an open-plan office is always helpful to the work of persons in every area of this space. As such, open-plan office acoustics involves combined management of co-occupancy, communication and concentration options required for performing individual activities. To find an optimum solution in an open-plan space and fully understand the complexity of its acoustics, employee activity, interactions and relative distances between workstations, work teams and departments should be taken into account for a given open-plan space. Site environment and the technical and architectural constraints should also be considered.
4.2 Methodology
This document aims to guide the design, building and layout of open-plan workspaces. It makes no recommendation on adopting or modifying the individual or social behaviour of people at work. However, it takes them into account as determining elements of the acoustic environment.
This document defines six types of open-plan space covering all existing activities and to which the reader shall refer for subsequently applying the related acoustic criteria. For each type of activity, this document sets target values and required values (see ILl and 112).
To comply with this document, all the required acoustic criteria defined shall be met for each space type. In the case of combining multiple activities, itis intended to respect set up values defined for each activity when defined. The chosen criteria are simple and verifiable, so they can he included and used in a contractual framework by all parties responsible for an open-plan space building or renovation process.
This document cannot anticipate individual perception, which is also linked to working conditions and the way rooms are used. The document therefore offers a comprehensive approach to assisting management of the acoustic component in open-plan projects.
It includes the following tools that shall be implemented:
— calculation method on DAS: specified in AnmixA
— a flow chart summarising the whole approach: specified in Annex B. in Hi. (renovation) and Ui (new building),
— an aid to analysing layouts: Workspace layout and room acoustics, specified in 1, 2 and 63…
— an aid to identifying existing acoustic treatments and priorities: specified in A.
Additional recommendations and information:
— a charter on collective use of open-plan spaces: etiquette, see Annex C.
— a model survey of the acoustics of open-plan offices for users: see Annex D.
— minimum optional requirements for measuring LAeqTduring the activity: see AnnexE.
— sound masking systems: see Annex F,
— acoustic indicators and values when the activity is not known yet: see Annex G.
The following tools can be used to support every step of a project as defined in Annex B.
5 Typology, acoustic challenges and requirements
5.1 General
Open-plan spaces shall be adapted to support the activities undertaken therein. The noise environment (number of noise sources, noise source level, etc.) can be very different depending on the type of activities.
The acoustic challenges specific to these spaces call upon closely linked notions of intelligibility and discretion: the same words can convey a helpful message for one employee and be a source of disturbance for another. A compromise between intelligibility for communication helpful to an activity and discretion shall therefore be sought in order to reduce disturbance at more distant workstations.
This document defines below six types of open-plan space, which cover all existing activities and to which the reader shall refer for subsequent application of the related acoustic criteria.
Open plan offices are not suitable for activities, which require confidential communication.
5.2 Space type 1: activity not known yet – vacant floor plate
5.2.1 Description
In this particular situation, the activity is not yet precisely defined. This is the case when property developers or a landholding trust are building office spaces. Yet, some attention needs to be brought to some basic acoustic criteria so that the offices are acoustically acceptable.
5.2.2 NoIse environment characterising this type of space
Any future fit-out is reliant on the basic provision of the base build. The base build therefore requires adequate flexibility to accommodate a diverse range of tenancy and fit-out requirements. The less flexible the base build provision, the less attractive it is to property agents who market it, and tenants who may want to fit out the space.
5.2.3 Acoustic challenges
A blank office space is developed to be later partitioned and furnished depending on the end user. Thereby, the main acoustic challenge is to create adequate condition for a later office planning corresponding to desired objectives. Assuming that external noise intrusion and building services noise are adequately controlled, and there is a good provision of sound insulation between adjacent tenant areas, the room acoustics requires consideration. For basic informative values, refer to national regulations or refer to Annex G.
5.3 Space type 2: activity mainly focusing on outside of the room communication (by telephone/audio/video)
5.3.1 Description of the activity
The activities iwrformed are diverse and mainly performed over the telephone: sales, technical assistance, information services, prospecting, surveys, emergency services, etc.
They can be defined as non-diverse and non-collaborative.
The spaces accommodating these activities are often referred to as customer relations centres, call
centres, contact centres. etc.
5.3.2 Noise environment characterising this type of space
There are multiple noise sources and they generate a significant ambient noise level, which can affect the vocal effort of all employees due to the Lombard effect.
Oral communication between employees can take place between calls.
Conversations within a team (colleagues, supervisor or manager) take place at the workstation (short conversations) or in areas adjacent to the open-plan space (long conversations, training sessions, etc.).
The general acoustic environment shall enable performance of intellectual work requiring a medium- to-high concentration level. It shall limit fatigue by ensuring the operator’s comfort, knowing that vocal effort is all the greater when ambient noise level is high.
5.3.3 Acoustic challenges
The main acoustic challenge is to limit aural exposure to the ambient noise and to the noise level of the personal telephone system.
The aim is to obtain a high level of intelligibility with a telephone conversation partner to minimise noise level in the ear and operator vocal effort.
There is little requirement for collaborative work, so greater discretion between workstations is sought. The method involves controlling and minimising reverberation and sound propagation phenomena.BS ISO 22955 pdf free download.Acoustics