The placement of a lockout device on an energy-isolating device, in accordance with an established procedure, ensuring that the energy-isolating device and the equipment being controlled cannot be operated until the lockout device is removed.
Merriam-Webster Online Dictionary
lockout (noun) the withholding of employment by an employer and the whole or partial closing of the business establishment in order to gain concessions from or resist demands of employees
nutrient blockage, nutrient lock, nutrient obstruction, nutrient barrier, nutrient exclusion
