What vacuum level does a hospital suction system need?

The figure is set at the outlet (the terminal unit). The plant has to run at a deeper vacuum than the outlet needs, so that the resistance of the bacteria filters and the exhaust back pressure can be overcome, and so that the losses in the pipework and across the terminal unit are covered.

HTM 02-01 (England, 2026 edition)

• At the outlet: at least 315.5 mmHg at the front of each terminal unit at a design flow of 40 L/min, held during the system design flow tests (paragraphs 4.46 and 10.3; paragraph 4.46 refers to BS EN ISO 9170-1).
• Pump rating: capacity is stated as free air aspirated in L/min with the pump at 475 mmHg (63 kPa) and at 450 mmHg (60 kPa) at the plant pipeline connection (10.27).
• Pump control: cut-in around 550 mmHg, subject to plant design, and cut-out expected at about 650 mmHg (10.31 and 10.32).

ACSS ET 03/2006 (Portugal, v.2024)

The Portuguese specification for medical gases and suction in hospital buildings sets a minimum relative depression of 60 kPa in the vacuum vessel and 53 kPa in the pipework (section 6.4).

Other references

ISO 7396-1:2016 sets the requirements for the design, installation, testing and commissioning of vacuum pipelines together with the compressed medical gases. In the United States the reference is NFPA 99, whose current edition is 2027. Use the document that the project specification names, with its figures and units as written.

ULTRAVAC plants

ULTRAVAC medical vacuum plants have a normal operating vacuum of −0.85 bar, according to the ULTRAVAC datasheet. The vacuum then available at each outlet depends on the pipeline design and is confirmed in the design flow tests.