ISO 23936-2-2011 pdf free download

ISO 23936-2-2011 pdf free download.Petroleum, petrochemical and natural gas industries Non-metallic materials in contact with media related to oil and gas production Part 2:Elastomers
Industries du pétrole, de Ia pétrochimie et du gaz naturel — Matériaux non métalliques en contact avec les fluides relatifs a Ia production de pétrole et de gaz — Partie 2: Elastomères.
7.2.1 General
This part of ISO 23936 defines test procedures for the prediction of the progressive degradation of elastorneric materials exposed to fluids at elevated temperatures over extended periods of time. It is applicable where it is necessary to forecast material life in a specific application and for directly comparing the performance of candidate elastomer materials. Other standards, such as API TR6J1. also provide methods to assess life of elastomer materials.
The objective is to assess the physical effects of the fluid on the elastomer and to thermally accelerate chemical reaction (if this occurs) between the fluid and the elastomer, causing tensile and related property levels to shift systematically towards a pre-defined limit of acceptability. The material is considered to have iailed (i.e. reached the end of its useful life) when this limit is attained. These data are then used to quantify service life and suitability for service.
By running exposure tests with test fluids at three different elevated temperatures above the operating temperature, three different times to reach the acceptance boundary will result, with the highest test temperature producing the shortest time to failure. Plotting the log of failure times against the reciprocal of the test temperature should result in a linear trend, enabling an estimate of service life at the operating temperature.
For accelerated testing, the upper test temperature should be limited to give some confidence that only service-relevant chemical andlor physical processes will occur.
The preferred test piece geometry is the tensile dumbbell; various standards apply (see Table 1). The ageing of moulded sheet, for subsequent stamping-out of tensile test pieces, is not allowed. The elastomer shall be tested in unconstrained mode: that is, free-standing, with fluid able to freely access all surfaces.
When extrapolating data from the present procedures, appropriate statistical techniques shall be applied. For example, if progressive degradation is apparently dependent on a single chemical ageing process, a method based on the Arrhenius relationship shall be used as described in Annex D. It is recommended that results always first be assessed on an Arrhenius basis. If an Arrhenius relationship does not exist or ageing does not occur, see Annex E for further guidance.
Test media, conditions, equipment, procedures and test report requirements are described in detail in Annex A.
7.2.2 Acceptance criteria for elastomers
The acceptance criteria shall be established prior to commencing the ageing test. ISO 23936-2-2011 pdf free download.