KANBrief 4/12

"A lot helps a lot": only partly true for emergency safety showers

The BG RCI (German Social Accident Insurance Institution for the raw materials and chemical industry) commissioned a research project in which the effects were tested of different flow rates of emergency body showers upon the efficiency with which chemicals were rinsed off. The results were presented at ACHEMA in June 2012. The motto "a lot helps a lot", relating to the required flow rate, was found to be inappropriate. This was an important finding for the further part planned for the European series of standards governing emergency safety showers.

Following burns or contamination with chemicals, emergency safety showers are intended to permit immediate flooding of the body (for body showers) or of the eye (for eye wash units). Requirements concerning emergency safety showers are set out in the EN 15154 series of standards, which now comprises four parts:

• Plumbed-in body showers for laboratories (Part 1)

• Plumbed-in eye wash units (Part 2)

• Non plumbed-in body showers (Part 3)

• Non plumbed-in eyewash units (Part 4) National DIN standards overlapping these standards in their subject areas were withdrawn; content from these DIN standards has however been incorporated into the European standards. Part 3 of DIN 12899, "Body showers for production and logistic sites", has been retained at national level. Under logistic sites, this standard also covers working areas, for example at refineries or docks, in which large quantities of chemicals may lead to contamination. In response to a French initiative, the conversion of DIN 12899-3 to a European standard is being discussed.

Flow rate: how much water must flow?

The required flow rate of the water had already proved topical for the OSH experts during development of Part 1 of the European series of standards, governing emergency showers for laboratories. With KAN's support, the OSH lobby was able to prevent the standard flow rate from being raised above 30 litres per minute in the standard, as had been desired by certain other countries. Experience had shown that in laboratories, more water did not automatically translate into greater safety, but would however lead to higher costs, owing to the need for more extensive installations or conversion work (See also KANBrief 2/2005, "A good shower is half the battle: emergency safety showers for laboratory use").

Studies by the BG RCI on the subject of rinsing properties

In preparation for the conversion of DIN 12899- 3 into a European standard, the BG RCI considered it appropriate to commission a study into the rinsing properties of showers for potentially very large-area contamination. The Fraunhofer UMSICHT research institute (Institute for Environmental, Safety and Energy Technology (UMSICHT)) in Oberhausen, the body conducting the study, presented the results to the public for the first time in June 2012 at ACHEMA (International Exhibition Congress on Chemical Engineering, Environmental Protection and Biotechnology) in Frankfurt.

The objective of the study was to examine systematically the influence of the water flow rate upon the effectiveness of decontamination on test dummies with the use of a range of substances and shower heads. Test flows of between 20 and 110 l per minute were used. The selected measurement method (employing conductivity sensors) enabled the rinsing rate for water-soluble contaminants to be measured reproducibly.

Even though the spray patterns differed between the different shower heads, in some cases considerably, no systematic relationship was observed between the flow rate of the water and the characteristic rinsing time for any of the shower heads. This suggests that in overhead body showers, a higher water flow rate (> 30 l per minute) does not necessarily improve the rinsing action.

In addition, certain further parameters were identified which have an influence upon the decontamination time. These include the type of shower head, the movement of the contaminated person during rinsing, and the facility for holding onto the shower head. However, the spray pattern of shower heads which yielded the shortest rinsing times in the tests and were therefore to be recommended from an OSH perspective failed to satisfy the requirements of Part 1 of the European EN 15154 series of standards with regard to the distribution of water from emergency showers.

The findings of the study are to be considered during conversion of DIN 12899-3 into a European standard. To ensure this, the BG RCI is participating in the standards committees at both national and European level (Contact: Dr. Brock, BG RCI).

Dr. Anja Vomberg