NOM-054-SCFI Home Appliances - Pressure Cookers - Safety

The standard “NOM-054-SCFI Household appliances - Pressure cookers - Safety”, published under the Official Mexican Standard (NOM), describes the technical characteristics and test methods that pressure cookers marketed in the national territory, designed to cook food quickly, with a maximum capacity of 21 liters, a maximum temperature of 127 degrees, a working manometric pressure greater than zero and up to a maximum of 150 kPa, must meet.

For the purposes of this standard, the following terms and definitions apply:

• Nominal capacity is the capacity stated on the pot by the manufacturer and expressed in liters.
• Actual capacity is the volume of liquid in liters that can be held in the body of the pressure cooker when the lid is open.
• The safety factor is the relationship between the hydrostatic pressure of the shell-shroud separation and the nominal operating manometric pressure.
• The rubber packing is a flexible element that is placed on the lid or body of the pot and provides hermetic sealing.
• The pressure indicator is a device placed on the pot lid that shows the pressure inside the pot while it is operating.
• The mango is the protruding part on both the lid and the body of the pot, which makes it easier to hold the pot.
• Pressure cookers are containers that are resistant to steam pressure, have adjustable lids and rubber seals, and are intended for cooking food quickly. They must have a safety valve or plug, pressure regulator, a lock that prevents opening when the pot is under pressure, and fixing parts such as handles or grips. They may also have a pressure gauge and other safety devices.
• This standard defines four concepts of pressure:
  • The hydrostatic pressure of the body-cover separation is the ultimate resistance to pressure.
  • The maximum working gauge pressure is the highest working pressure allowed by this standard, i.e. 150 kPa.
  • Nominal working gauge pressure is the working gauge pressure determined by the manufacturer.
  • The actual operating gauge pressure is the gauge pressure at which the pressure cooker actually operates and is determined by the operation of the pressure regulator.
  • The pressure regulator, a pressure regulating device located on the lid of the pot, aims to reduce the risk of clogging of the pot. This device works by opening when the internal pressure exceeds the specified limit and relieving excess pressure, and closing when the pressure decreases.
  • The unlocking mechanism is the mechanism that prevents the pot from being opened when there is pressure inside the pot.
  • The safety valve or fuse plug is a mechanism that is attached to the lid of the pot and ensures that it operates in case of excessive pressure.

Pressure cookers subject to this standard are classified into 4 types according to the lid and body material:

• Type 1 Both sides are aluminum
• Type 2 Both sides stainless steel, with or without external diffuser
• Type 3 is a combination of Types 1 and 2.
• Type 4 Other materials suitable for pressure cooking

In this standard, the requirements for pressure cookers are determined as follows:

• The nominal working gauge pressure allowed by this standard is 150 kPa.
• It should be between 88 percent and 115 percent of the nominal working gauge pressure. In no case should the actual working gauge pressure be greater than the maximum working gauge pressure verified in accordance with this standard.
• The safety factor defined in this standard must be at least 5.
• Hermeticity: The internal pressure that the pots must withstand without leaking must be at least 5 times the actual working gauge pressure for 1,5 minutes.
• The hydrostatic pressure that the containers must withstand without causing leakage or permanent deformation must be at least 5 times the nominal working gauge pressure for 2 minutes.
• When performing the hydrostatic pressure test for body-lid separation, the minimum value at which the lid separates from the pot body should be greater than 5 times the nominal working gauge pressure. Failure may occur due to deformation or leakage without bursting or rupture.
• The safety valve or fuse plug should be operated when the pot has a maximum internal pressure of 2,5 times the actual working gauge pressure.
• The rubber seals used on pot lids should not have any defects such as tears, bubbles, holes, missing parts or foreign matter. After the packaging is tested, it should not leave any stains when cleaned and dried with a clean, white cotton cloth. After the packaging is subjected to an accelerated aging test with steam cycles, at actual operating gauge pressure Must withstand a 5 minute cycle without leakage. After being subjected to the dry aging test, the package must withstand a 5 minute cycle at the actual operating gauge pressure without leakage. After being subjected to the oven aging test, the package must withstand being bent 5 degrees on itself for 180 seconds without showing breakage, delamination or separation.
• The temperature of the handles and grips of pressure cookers should not exceed 50 degrees under normal operating conditions. The non-flammability of the material of these materials should be verified according to this standard.
• The pot pressure regulator should regulate actual operating gauge pressure between 88 percent and 115 percent of the nominal operating gauge pressure.
• Actual capacity shall be measured in litres and expressed in litres, in whole numbers or integers and decimals, and shall not be less than 10 per cent of the actual capacity stated by the manufacturer for pots of 95 L or less, and 10 per cent for pots of more than 90 L.
• In pressure cookers without a trigger system on the handle, this device must prevent the cooker from opening by applying a force of 4 N when there is a pressure of 120 kPa inside the cooker.
• If a pressure gauge is available, it must be sensitive enough to operate at a pressure of 4 kPa.

Our organization, which has been trying to support businesses from every sector with its wide range of testing, measurement, analysis and evaluation studies for years, has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. In this context, testing services in accordance with the "NOM-054-SCFI Home appliances - Pressure cookers - Security" standard are also provided to businesses.