What safety and first aid equipment is required by law will vary from industry to industry and from country to country. There are, however, only a few recognised standards governing the design and performance of safety showers specifically. Ensuring compliance with these standards should meet the operational requirements of almost all health and safety legislation.
It needs to be strongly iterated that simply having a safety shower that performs in compliance with these standards is NOT enough to ensure compliance with health and safety regulations. Showers and eye baths are simply first aid equipment and so only form a small part of any safety plan. The main focus of any safety plan should be to prevent accidents from occurring in the first place and no first aid equipment is able to help with this. That being said, if disaster does occur then the provision of quality first aid equipment can save lives and remove litigation risk, so compliance with these standards is of the utmost importance.
There is no complete EU or UK standard that covers all types of shower for all types of installation. The existing EU 15154 standard has 4 completed parts which will cover plumbed in showers in laboratories and plumbed in eye showers in both labs and industrial / logistics sites and tank showers (non plumbed) for all sites but there is no finalised standard covering plumbed in showers for industrial (non-lab) sites. This should be rectified when parts 5 is finalised.
The lack of clear EU standards does not mean that any old shower will suffice in the world. Employers still have a legal requirement to provide sufficient first aid equipment, the lack of clear standards simply means defining the word sufficient is more problematic. Where applicable to the EU standards should be used but in areas / products not covered guidance from other standards would be sensible.
The America ANSI Z358.1-2004 / 2009 is a more or less holistic standard covering most types of shower and eye bath and its scope is for all types of working environment. This completeness means it is often used as the “go to” standard when more local standards are lacking. Alternatively the German DIN 12899-3:2009 is a standard that covers Plumbed and Tank body showers for industrial and logistics sites, this plugs the very big gap in the European EN15154 standards. A UK company using either the American or German standards would in all likely hood be meeting its obligations. Although it may be advisable to steer towards the German standards as these will in all likely hood from the basis of the EN15154 part 5 when completed.
It should be stressed again that merely having showers that meet certain performance standards is only a small part of meeting ones health and safety obligations.