This study investigates leak hole sizes in more than 40 plate heat exchangers (PHE) to support the development of improved safety standards for the use of flammable refrigerants, such as R290 (propane). Although significant progress has been made in refining safety guidelines in recent years, there remains a lack of specific leak data for PHEs, which are widely used components in refrigeration, air conditioning, and heat pump systems. The absence of such data introduces uncertainty into risk assessments. This, in turn, may lead to uncertain design constraints, hence impacts allowable refrigerant charge limits, and  leads to higher system costs due to the need for added mitigation measures. The study aims to fill this gap by providing targeted information on leak hole characteristics s ...