SIL analysis

Process engineering and design using Visual Basic 

Definitions of frequently used terms in SIL analysis are presented in the following text. For detailed definitions, refer to lEC 61511 (Part 1) [23]. 

This is the ratio of the detected failure rate to the total failure rate of the component or subsystem as detected by diagnostic tests. Diagnostic coverage does not include any faults detected by proof tests. 

---

This oxidative reaction with the oxide surface has been observed even when the triosmium clusters are first bound to anchored ligands, such as PPh2 (0112)2 SIL or 118(0112)3 SIL. Analysis of the osmium L(III) edge EXAFS of the product of Os (00) j 2 with the latter functionalised oxide was entirely in accord with the structure Os H (00) j q(M-S(CH2) 3SIL) with Os-Os bond lengths of 2.848. On thermal decomposition at 48 h, a new component was... 

Signoret, J-P. Dutuit, Y. Rauzy, A. 2007. High Integrity Protection Systems (TUPS) Methods and tools for efficient Safety Integrity Levels (SIL) analysis and calculations. 

In practical terms it is important that methods used by industry SIL analysis are clear and simple to adapt. Here, one may distinguish two situations ... 

Terminology used in the loss prevention profession that may be nnfamiliar to those outside the discipline, e.g., ALARP, HAZOP, SIL Analysis, Layers of Protection Analysis, etc. 

K. Bingham, P. Goteti, Integrity of HAZOP and LOPA/SIL Analysis Best Practice Recommendations, The Instmmentation, Systems and Automation Society, October 2009. 

Note Empty cells indicate that SIL analysis is not required. Normally, a process industry is not designed for SIL 4 and above. 

The purpose of this exercise is to establish at what SIL this design needs to be maintained. As explained before, the SIL analysis will be conducted for all three different scenarios (1) financial, (2) health and safety, and (3) environment and asset. 

For low molecular weight aliphatic acids, try TMSDEA reagent. Otherwise, use MSTFA, BSTFA, or TRI-SIL BSA (Formula P). For analysis of the keto acids, methoxime derivatives should be prepared first, followed by the preparation of the trimethylsilane (TMS) derivatives using BSTFA reagent. This results in the meth-oxime-TMS derivatives. 

The use of a fused silica capillary column for the GC analysis of the neutral oil extract has provided the means for improving the resolution of components in a more inert system. The sultones are determined by temperature-programmed GC over CP-Sil-5 CB (methyl silicone fluid) in a 25 m x 0.2 mm fused silica capillary column using nonadecane as internal standard. A sample split ratio of 1 100 is recommended for a 3-pl injection. 

The catalyst testing was carried out in a gas phase downflow stainless steel tubular reactor with on-line gas analysis using a Model 5890 Hewlett-Packard gas chromatograph (GC) equipped with heated in-line automated Valeo sampling valves and a CP-sD 5 or CP-sil 13 capillary WCOT colunm. GC/MS analyses of condensable products, especially with respect to O-isotopic distribution, was also carried out using a CP-sil 13 capillary column. For analysis of chiral compounds, a Chirasil-CD capillary fused silica column was employed. 

The products were identified by comparing the retention times of the reaction products with commercial compounds, and by GC-MS analysis in a Hewlett-Packard 5973/6890 GC equipped with an electron impact ionization at 70 eV detector and a cross-linked 5% PH ME siloxane (0.25 mm coating) capillary column. The reaction products were separated from the catalyst with filter syringes and analyzed in an Agilent 4890D and a Varian 3400 GC equipped with a flame ionization detector, and CP-Sil 8CB (30 m x 0.53 mm x 1.5 pm) and DB-1 (50 m x 0.52 mm x 1.2 pm) columns, respectively. Decane was used as an internal standard. The catalyst was thoroughly washed after reaction with acetonitrile, acetone and water, and dried overnight under vacuum at 40°C. 

The reaction solution was diluted with 36 mL of water. The unreacted free drug and other low molecular weight materials were removed by a Centriprep-10 concentrator. Purification was repeated until HPLC analysis (Bio-Sil TSK-250) of the product indicated the absence of free drug. The final purified product was lyophilized to afford 483 mg of a yellow solid. This solid product was readily soluble in water or aqueous buffer. The amount of drug covalently bound to MVE was estimated by the absorbance at 303 nm using a molar extinction coefficient of 17.03 x 103. The MVE-y-hy-MTX contains 26% methotrexate-y-hydrazide by weight. 

Analysis of reaction products - Liquid reaction products were analyzed by GC using a capillary column CP-Sil-8CB (WCOT Fused Silica - stationary phase 5% phenyl-methyl-polysiloxane, length 50 m, ID 0.32 mm, OD 0.45 mm film... 

General References Guidelines for Hazard Evaluation Procedures, Second Edition with Worked Examples, American Institute of Chemical Engineers, New York, 1992 Layer of Protection Analysis A Simplified Risk Assessment Approach, American Institute of Chemical Engineers, New York, 2001 ISA TR84.00.02, Safety Instrumented Functions (SIF)—Safety Integrity Level (SIL) Evaluation Techniques, Instrumentation, Systems, and Automation Society, N.C., 2002. 

Ruvalcaba-Sil, J. L., Salamanca, M.A. O., et al. (1999). Characterization of pre-Hispanic pottery from Teotihuacan, Mexico, by a combined PIXE-RBS and XRD analysis. Nuclear Instruments and Methods in Physics Research B 150 591-596. 

Statutory Instrument No. 1342 (1995) The Fertilisers (Sampling and Analysis) Regulations 1996. The Stationery Office, London (web version). The title page of the SI may be downloaded from the following website http //www.hmso.gov. uk/si/sil 996/Uksi 19961342 en l. htm with Schedule 2, Methods of Analysis at http //www.hmso.gov.uk/si/sil 995/Uksi ... 

A few gas chromatography (GC) and liquid chromatography (LC) studies have been reported. Eor example, PCDDs have been separated on a 50m x 0.25 mm polar fused silica capillary GC column (CP Sil-88, Chrompack) with helium as carrier gas and Fourier transform infrared (FTIR)/MS detectors <1997ANC1113>. Furthermore, a highly sensitive and accurate GC-MS method for rapid quantitative analysis of 1,4-dioxane in water has been described <1997JCH(787)283>. 

System (4) has been described for the analysis of corticosteroids in human adrenal tissues [152]. Prior to the HPLC analysis, the corticosteroids were extracted from adrenal tissues by acetone. The permissible columns were 20 cm X 2.4 mm, consisting of Zorbax-SIL (for more polar compounds) or Zorbax-CN (for less polar compounds). The mobile phase was 9 4 1 cyclohexane-dichloromethane-ethanol or aqueous methanol, and eluted at a flow rate of 0.4 mL/min. Using a UV detection wavelength of 254 nm, sample recoveries were 78.5-99.5%, and the relative standard deviation was 2-5%. 

Oxyfunctionalization reactions of n-alkanes are carried out at room temperature and atmospheric pressure with t.BHP as oxidans and acetone as solvent. Product analysis was done with GC on a 50 m CP Sil-88 capillary column from Chrompack. 

Supercritical fluid chromatography (SFC) has also been used in phospholipid analysis. According to Lafosse et al., phospholipid classes can be separated by SFC using a simple isocratic solvent consisting of 78.4/21.6 (w/w) mixture of carbon dioxide and a mixture of methanol, water, and triethylamine (95/4.95/0.05) in combination with a Zorbax Sil stationary phase detection was performed by evaporative light-scattering (20). 

Another approach would be to derivatize cyclamate prior to analysis. Cyclamate can be determined by HPLC and UV detection at 314 nm after conversion to A/,/V-dichlorocyclohexyl-amine. Derivatization can be carried out directly in the sample or after extraction and cleanup. /V,/V-Dichlorocyclohexylamine is separated on a reverse-phase column (Nucleosil Cl8 or Fine-pak SIL Cl8 T-5) with a mobile phase of methanol water, 8 2 v/v (43,46). Cyclamate can also be determined at 585 nm after postcolumn derivatization with methyl violet 2B as described by Lawrence and Charbonneau (16). 

It is not clear yet whether any of the investigated parameters can be used for new diagnostic aspects of individual patients, but it can, at least, be used for observation and follow-up investigations of groups of patients. The analysis of plasma level progression, especially of sICAM-1, sIL-2R and sE-selectin, provides an additional aspect in the evaluation of allergy therapies and their functional mechanisms. 

---