Distinguish gas from solution
International Chemical Safety Card 0414 concerns anhydrous ammonia, CAS 7664-41-7, also known as refrigerant R717. An aqueous solution has different exposure conditions and must be assessed using its own safety data sheet.
Concentration, temperature, pressure and handling method affect the consequences of a release. Identifying only “ammonia” in the inventory does not allow sufficient measures to be selected.
Recognise possible harm
The ICSC describes inhalation toxicity and corrosive effects on the eyes, skin and respiratory tract. Contact with liquid released from a pressurised system can also cause cold injuries. It should not be treated solely as an odour problem.
Assessment must also include the system’s physical hazards and conditions under which a fire risk may exist. Measures for a routine operation are not automatically valid during a leak.
Assess each intervention
Royal Decree 374/2001, applicable in Spain, requires assessing the agent’s properties and actual working conditions. At an installation, distinguish operation, inspection, maintenance and responses to abnormalities.
Before equipment is opened or worked on, technical planning, assigned responsibilities and coordination with external companies must be in place. This article does not replace the installation’s specific isolation, intervention or commissioning procedures.
Prevent releases
Circuit design, integrity and maintenance form a first barrier. Checks must address components, joints and intervention points, together with ventilation and detection required by the assessment.
An alarm requires maintenance, response criteria and people who know what to do. Installing it alone does not control exposure or replace leak prevention.
Check exposure and protection
Measurements must address the analysed scenario, including brief operations that may produce peaks. The INSST Occupational Exposure Limits database provides current references and their comparison periods.
Protective equipment is selected for the substance, expected concentration and task. Protection for ordinary work must not be confused with equipment for intervention in an unknown or hazardous atmosphere.
Prepare for emergencies without improvisation
The plan must establish how to raise the alarm, leave or isolate areas and request specialist intervention, as well as identify potentially affected people. Leak control must not be assigned to anyone lacking training, equipment and authorisation.
Routes and assembly points must account for the installation’s conditions. After an incident, investigate the cause and verify safety before authorising return, rather than relying solely on a reduction in smell.
Hypothetical example: refrigeration maintenance
A company reviews a periodic intervention on its refrigeration installation. It finds that the contractor knows the equipment but not the site’s warning system or assembly point.
It incorporates that information into coordination, verifies responsibilities and resources, and rehearses communication. Prevention improves both the technical intervention and the response of people working nearby.
