Positive Pressurisation Ventilation (PPV)

Product Features

The Daisy Positive Pressurisation Venting (PPV) Unit has been designed to provide an alternative approach to the natural 0.4m2 permanent ventilation within basement lobbies.

Section 2.47 of Approved Document B1 (ADB) identifies that where lobby ventilation is required for B1 means of escape, to protect the stair this can be achieved by natural ventilation or mechanical smoke control. Section 7.6 of the Smoke Control Association (SCA) Guidance document on Residential Buildings – 2015 provides guidance on how to meet the mechanical smoke control requirements using pressurisation. The BS9991:2015 references the SCA document as a source for further design guidance.


The PPV unit injects air into the protected lobby/stair to raise to a higher pressure to prevent the ingress of smoke from the car park.

The unit incorporates duty and standby fans, duty and standby fire dampers, smoke detector interface, single phase automatic electrical change over switch, controls, status LED and a volt free contact for 3rd   party monitoring. All the above is located within the decorative PPV enclosure box.

The system is operated by a smoke detector located on the car park side of the lobby door. The system continues to run until the smoke detector is reset.




  • PPV unit prevents smoke entering the stair.

  • PPV unit occupies minimum space.

  • The 0.4m2 expensive fire rated duct can be omitted.

  • Low car park heights or stepping services around the duct are not a concern.

  • The car park smoke clearance system does not need to be enhanced and can remain at 10 air changes per hour.

  • Can be used with natural ventilated car parks.

  • No expensive fire shutters required or control of inlet air paths.

  • No expensive CFD justification of the lobby de-pressurisation.

  • Robust solution that keeps smoke out of the stair core.

  • Cost effective solution meeting the ADB & SCA Guide.

Product Links

PPV Review

PPV Technical Sheet

PPV Installation & Maintenance

PPV Builders Work Drawing

DMS DNS01 PPV Application

PPV Test Video

PPV Escape Video

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Product Features


  • Certificated fire damper to BS EN1366-2

  • ISO 5801:2008 single phase duty and standby fan.

  • BS 5839 Smoke Detector.

  • Can run from 3rd party IO.

  • Single phase power supply 230v, 0.5 kw.

  • Alternative power supply can be taken from a separate phase.

  • The fan speed to develop 50pa is set up during commissioning by turning a voltage regulator switch.

  • No specialist knowledge or systems required to set up.

  • The structural hole for the damper is 0.8m wide x 0.3m high and the sides need to support a weight of 47kg.

  • The PPV unit measures 0.35m high, 0.83m long and 0.3m deep.

  • Fan is capable of developing 0.5m3/s at a static pressure of 50 pa.

  • Casing finish to white RAL 9003.

  • Health/Fault LED.

  • Fault mode relay.

  • Allows lobby/stair to be pressurised with  British Standard fitted fire doors in an air tight  lobby.

  • Unit should be selected in accordance with guidance note DMS-DN01 design criteria.