1.
Revision No.4
11/12/2017
_____________________________________________________ ___________________________
PRECISION UK Ltd,
CPX Technology Building,
Stockport, Cheshire, UK, SK7 5BW
Tel: +44 (0) 161 487 2822
Fax: +44 (0) 161 487 2816
Email: info@precisionuk.co.uk
Technical Specification
Compact Area Valve Service Unit (AVSU-C)
Product Description
The CPX Compact Area Valve Service Unit (AVSU-C) can be used in conjunction with other area valve
service units (AVSU), And can be manufactured to incorporate the CPX Digital Local Area Alarm (CPX-
DA) which meets and fully complies with the latest standard
HTM02-01 and BS EN ISO 7396-1.
The CPX Compact Area Valve Service Units are CE marked under Annex X of the Medical
Device Directive 93/43/EC and classified as a class IIb medical devices and are supplied with a
Certificate of Origin for review.
All CPX Compact Area Valve Service units are manufactured under an ISO 13485:2003 quality
management system. A copy of the certificate of registration will be provided.

2.
Revision No.4
11/12/2017
_____________________________________________________ ___________________________
PRECISION UK Ltd,
CPX Technology Building,
Stockport, Cheshire, UK, SK7 5BW
Tel: +44 (0) 161 487 2822
Fax: +44 (0) 161 487 2816
Email: info@precisionuk.co.uk
Definition of Use
The AVSU-C is intended to be used as a means of local isolation on medical gas pipelines during normal
installation and maintenance or in the event of an emergency, offer leak free connections as soon as they are
installed to corresponding medical gas pipelines and are safe and easy to use.
The Unit is designed to be mounted directly into a medical gas pipeline system via the copper tail pipes
supplied, and can be located within a wall, Ceiling void or any location where general access is required.
The copper pipe stubs are of sufficient length to enable brazing directly to the medical gas pipeline system
utilising fluxless brazing to WKO (82) 1.
The CPX AVSU-C incorporates a ball valves, with downstream NIST connectors, mounted in a lockable box with
emergency access. A blanking facility is supplied as a secondary means of isolation, with the intention to
provide a physical barrier to the gas supply, to eliminate any risk of contamination during the initial installation
of the medical gas pipeline system or any upgrade/maintenance work.
Pressure transducers can be fitted inside the enclosure to enable local monitoring from the CPX Local Area
Digital Alarm, a hospital central alarm system or BMS if required.
The chassis and door are manufactured from double primer and epoxy powder coated steel for protection. The
AVSU-C chassis has universal mounting points for securing the installed valves, A colour coded service identity
label fitted on the individual valve handles and pressure Gauges for secondary monitoring of the pipeline
pressure. The door locking mechanism has a 90° clockwise turn stainless steel assembly with minimum 20,000
combination lock types and incorporates an emergency access system.
Each AVSU-C has a secondary gas identification label mounted with each pressure gauge bearing the relevant
gas name or symbol and its relative BS 1710 colour code.
An Anti-tamper device with monitoring to a Building Management System (BMS) is an available option on each
Compact Area Valve Service Unit upon request.
A NIST connection with integral Non-Return Valves is fitted for each gas service. AVSU-C ball valves are
manufactured from die-cast nickel plated brass alloy with male threaded 2 piece valve, chrome plated brass
ball, PTFE seals and flat face connections to allow removal of the valve without the requirement to distort the
pipeline. AVSU-C ball valves are operated by a RED die cast quarter turn handle and benefit from low torque
operation and are easily replaced if required for maintenance. AVSU-C ball valves also incorporate blow out
proof stems.
Through spades are provided on the downstream side of the valve and each valve is also provided with a
blanking spade for deployment during installation or modification of the system without interruption of the
main supply.
The NIST connectors, to facilitate easy purge for testing and emergency supply, form part of each stub pipe
and incorporate a 100% seal check valve with metal seat thus avoiding the possibility of degradation over time.
The AVSU-C connection stub pipes protrude outside of the box by a sufficient amount to avoid scorching when
brazing to pipeline, and allow for up to 6 gases to be vertically brazed into the supply pipeline to reduce
soldered joints.

3.
Revision No.4
11/12/2017
_____________________________________________________ ___________________________
PRECISION UK Ltd,
CPX Technology Building,
Stockport, Cheshire, UK, SK7 5BW
Tel: +44 (0) 161 487 2822
Fax: +44 (0) 161 487 2816
Email: info@precisionuk.co.uk
Configuration
The AVSU-C is available as either surface or flush mounted. Other options include -
• With or without Valve viewing Window.
• Any combination of 1 to 6 gas services (O2, N2O, O2/N2O, MA4, SA7, VAC, CO2 & N2) in sizes of
22mm as standard. (Other sizes are available on request)
• either with or without the CPX Local Area Digital Alarm and Transducers,
With any combination of the above options available, The AVSU-C is designed to fit virtually any customer
requirement.

4.
Revision No.4
11/12/2017
_____________________________________________________ ___________________________
PRECISION UK Ltd,
CPX Technology Building,
Stockport, Cheshire, UK, SK7 5BW
Tel: +44 (0) 161 487 2822
Fax: +44 (0) 161 487 2816
Email: info@precisionuk.co.uk
Mounting details
CPX Local Area Digital Alarm
CPX Local Area Digital Alarm Systems are designed to meet, and fully comply with the latest standard BS EN
ISO 7396-1. They are duly CE marked CE no. 0086 and a Copy of our CE certificate from the notified body will
be submitted along with a Certificate of Origin.
CPX Local Area Digital Alarm Systems are designed to monitor piped gas pressure (high and low pressure on up
to six services) Via Pressure Sensors located within the AVSU-C, or in Theatres, Intensive Care Units,
Recoveries, Private Rooms and Wards etc.
CPX Local Area Digital Alarms provide indication of the condition of gas (Normal, High or Low Pressure) at the
point of use, providing live pressure reading by monitoring the internal pressure of the pipeline.
A single Pressure Transducer is fitted to each pipeline with an end of line monitoring capability to the alarm
panel, enabling the alarm panel to detect any faults on the system wiring or signal transmission.
The CPX Local Area Digital Alarm Panel incorporates 18 conditions and can display up to six services each with
normal & two fault conditions.
The CPX Local Area Digital Alarm panel incorporates a touch screen and is configurable to each application up
to 6 gas types, all programmable using engineers access code.
Each condition has a green normal lamp, gas type, pressure reading (Bar).
Each fault condition causes a red flashing on this gas type and audible alarm. The Audible alarm can be muted
for 15 minutes by pressing on the affected gas type for 2 seconds.
To transmit digital BMS alarm conditions using MODBUS data protocol, or for display onto a computer
interface alarm system, Several CPX Local Area Alarms May be connected using just 3 core Wire with a
maximum 250mtrs span between alarms.

5.
Revision No.4
11/12/2017
_____________________________________________________ ___________________________
PRECISION UK Ltd,
CPX Technology Building,
Stockport, Cheshire, UK, SK7 5BW
Tel: +44 (0) 161 487 2822
Fax: +44 (0) 161 487 2816
Email: info@precisionuk.co.uk
Operation
When a pressure change due to high or low pressure is detected, the appropriate gas type will flash and the
audible alarm will sound. Pressing on the affected gas type, on the touch screen, for 2 seconds will silence the
audible alarm. If the alarm conditions remain the audible alarm will re-trigger after 15 minutes, requiring re-
muting.
Quality
The CPX Compact Area valve service Units are manufactured in the UK under BS EN 13485 Medical Devices:
Quality Management Systems.
Product Cleanliness
The Compact Area Valve Service Unit is cleaned and degreased for oxygen service and free from all particulate
matter and toxic residues and has a maximum carbon level of 0.2mg/dm²as detailed in ISO 15001. Each
assembly is individually end capped and polythene wrapped to maintain cleanliness.
Pipeline Jointing
The AVSU-C copper stub pipe is manufactured to BS13348 for connection to the pipeline system and joints
shall be made on site using copper, phosphorus and silver brazing alloy CuP282 to BS EN 17672:2010. Brazing
should be carried out using oxygen free nitrogen as an inert gas shield to prevent the formation of oxides on
the inside of the pipe. Copper pipes shall be cut square with the pipe axis using a sharp wheel cutter wherever
possible, and be cleaned to remove any cuttings or burrs.