BS EN 521:2006 pdf download – Specifications for dedicated liquefied petroleum gas appliances — Portable vapour pressure liquefied petroleum gas appliances
This requirement shall also be met when the appliance is fitted with optional parts (for example: lampextension posts).
These requirements shall be met under the test conditions described in 6.5.2.
5.6Soundness of the gas circuit assembly
Holes for screws,pins,etc, intended for the assembly of components shall not open into the space reservedfor the gas ways leading to the injector.
The soundness of parts and assemblies connected to the gas circuit shall be assured by means of metal-to-metal joints or joints with seals (for example,flat-faced joints,O-rings or gaskets), i.e. excluding the use of anyproduct which ensures soundness in the threads.For parts that do not require to be dismantled during normalmaintenance, for example taps, the use of thread sealing compounds is permitted.
Removable components or the threaded parts of the gas pipework which may be dismantled during normalmaintenance shall remain sound after five disconnections and re-connections in accordance with theinstructions, if necessary after changing a gasket.
Soft solder (see definition in 3.8) shall not be used to ensure the soundness of the gas circuit. However it ispermitted for internal connections within the gas circuit when they do not involve soundness. Conformity shallbe verified based on the manufacturer’s specifications.
Under the test conditions defined in 6.6.1, during each of the tests no.1 and 2, the leak shall not exceed0,07 Ih (1 013 mbar, 20 C).This requirement shall also be met after all the tests on the appliance have beencarried out, but before any dismantling of parts subjected to the soundness tests.
5.7Connections
5.7.1General
Whatever the type of gas container (pierceable cartridge, cartridge fitted with a valve, cartridge with or withoutcentre boss，refillable reservoir….),when following the instructions, connection of the appliance to the gascontainer shall be easy with minimal, if any, gas leakage.
For appliances with direct rigid connection to the gas container(s), the CE Type Examination technical file forthe appliance shall include diagrams and specifications of the gas containers (including their gas outletconnections) intended for the gas supply to the appliance.
5.7.2Appliances directly fitted to the gas container
5.7.2.1 Appliances fitted to pierceable cartridges
a) design/construction of the appliance shall be such that there is no foreseeable replacement procedure
sequence possible which can lead to an unsafe and/or unintended piercing of the cartridge by the user.
(See in Annex C examples of authorized solutions);
b)The cartridge holder and the piercing device shall be such that:
1) the piercing is centred in the position provided;
2)soundness is ensured before piercing;
3) after the fitting of the cartridge，it shall not be possible to remove it,instantaneously and
unintentionally, without first having to remove the piercing device.
Diagrams showing the correct sequence for the fitting of the cartridge to the appliance shall be marked on theappliance.
5.7.2.2 Appliances fixed onto cartridges with female valve and threaded centre boss as defined inEN 417 (see Figure 1)
5.7.2.2.1 The female thread of the adaptor (Figure 2) designed to be fixed onto the thread of the centreboss valve is defined as follows:
7/16 in – 28 threads Unified Form Special – (see Figure 3);- major diameter
5.7.2.2.2 The part of the adaptor, with a full thread, shall be 3,10 mm± 0,1 mm long (see Figure 2 a)).5.7.2.2.3 The thread shall penetrate fully into the seal groove without reduction in form.
5.7.2.2.4 A valve actuator shall be fixed on the axis of the adaptor in such a way that it allows the drawingoff of gas from a full cartridge in accordance with 5.7.1.The valve actuator shallallow the release of gas fromthe cartridge when the appliance is screwed onto the valve with a minimum torque of 3 Nm.
5.7.2.2.5 The diameter of the valve actuator shall not exceed 2,20 mm if it is solid and shall be between3,10 mm and 3,15 mm if it includes a gas way as indicated in Figure 2 b). The valve actuator shall beconcentric with the “7/16 in – 28 unified form thread” subject to a tolerance of 0,15 mm (see Figures 2 a) and2 b))-
5.7.2.2.6 At the point where the valve actuator comes into contact with the valve seat, the valve actuatordiameter shall be at least 1,70 mm (see Figure 2 a)).
NOTE lt is recommended that adaptor manufacturers contact manufacturers of cartridge valves to establish thepreferred design (see Figure 2 b). The valve actuator shown in Figure 2 b) comes in contact with the inner seal of thevalve ensuring complete soundness when the cartridge is fitted.
5.7.2.2.7 A seal groove shall be machined at the bottom of the threaded part so as to centre and secure aseal (see Figure 2 a). This seal shall come into contact with the valve centre boss. The seal and the sealgroove shall be such that there is no visible and permanent distortion of the threaded centre boss when theappliance is screwed onto the valve with a torque of 12 Nm.
5.7.2.2.8 The length of the valve actuator shall be such that it does not penetrate into the valve for adistance exceeding 4,15 mm below the plane of the upper side of the centre boss (see Figure 4, dimension X)when the appliance is screwed onto the’valve with a torque of 12 Nm.
5.7.2.2.9 The inlet of the adaptor prior to the thread shall be a maximum of 2,00 mm deep and have adiameter of between 11,0 mm and 12,0 mm. In addition,the inlet of the adaptor shall begin with a1,0 mm×45° chamfer (see Figure 2 a)).
5.7.2.2.10 The diameter of the adaptor which penetrates the valve seal groove shall not exceed 22,90 mm.This part shall not extend more than 3,5 mm from the start of the adaptor thread (see Figure 2 a)).