A number of organisations have got together to produce a Corporate Governance Code for the Community and Voluntary Sector. It has three different levels depending on the nature of the organisation concerned. Purely voluntary, it represents a good basis for corporate governance in these organisations.
The website at www.governancecode.ie provides all of the relevant documentation together with guidance on finding the most appropriate Code of Governance for an organisation and other relevant tools. If your museum or gallery is run on a voluntary basis or by a small Limited company this could be a useful guide to best practice.