<p> Agenda Item: 650-731 </p><p>Title: Inlet Diffuser Clarification Date: January 28, 2011 Contact: Name: Larry Hiner Company: Chicago Bridge & Iron Company Phone: 815-439-6125 E-mail: [email protected] Purpose: To clarify the purpose of inlet diffusers Source: RFI from Larry Hiner 4/12/2010 Revision: 1 Date 5/14/2011 Impact: Increased safety Clarity of requirements Background: Note that revisions for rev 0 are shown in red, revisions based on comments in the Spring 2011 ballots are shown in blue. </p><p>The following was the inquiry of 4/12/2010</p><p>“When the Purchaser requests an inlet diffuser to be installed in a tank, is it automatically a requirement that the 1 m (3ft) per second maximum velocity apply to the diffuser design?” </p><p>Response: “No, however an agenda item will be taken out to clarify the requirements.”</p><p>______</p><p>The following captures some of the discussion in the committee Fall 2010 meeting. </p><p>Possible inclusion into the agenda item As background and discussion for the modification of API 650, H.5.6, the agenda item will state something to the effect - Diffusers can be used to reduce or redirect flow rates to avoid impingement on internal components and avoid pushing product onto the floating roof. Additionally, diffusers can be used to help disperse any gases introduced into the tank. Diffusers should not be considered as the means of reducing stated initial velocity limits (3 ft / sec per API RP 2003) as a means of reducing risk of static discharge.</p><p>Some general information not included in the inquiry</p><p>From API 2003 4.1.5 Preventive Measures A variety of preventive measures can be considered to reduce the risk of static discharge. Not all of these measures are applicable in every situation. Examples include the following. To prevent charge generation: a) avoid splashing and misting operations (e.g. in filling operations); b) limit initial fill rates and maximum flow rates (e.g. in filling operations);</p><p>4.2.1.1 Initial Loading Top loading down spouts and bottom loading outlets should be equipped with spray deflectors. Splash filling should be avoided. The liquid velocity in the fill line should be limited to 3 ft/s (about 1 m/s) until the outlet is submerged to prevent spraying and to minimize surface turbulence.</p><p>Page 1 of 3 Proposal: Revise the wording to clearly state that diffusers shall not be used as a means of reducing velocity during fill operations with low product levels. State when diffusers can be considered and where to specify requirements. </p><p>Specific 3.9 inlet diffusers: Internal fill line piping with impingement plate, baffles, slots, or lateral changes: openings. to reduce the velocity of the flow entering a tank. Diffusers serve various functions such as to limit splashing and misting of product, to avoid prevent product impingement on internal components, or to help and disperse any gases introduced into the tank. Diffusers should not be considered as a means of reducing initial fill velocity limits to comply with 3 ft / sec recommendations of API RP 2003.</p><p>5.8.11.2 Inlet diffusers shall be provided if requested when specified by the Purchaser or requested by the internal floating roof supplier manufacturer . Requirements shall be included in the Data Sheet in Table 4 OTHER TANK APPURTENANCES* section of the Data Sheet, Table 4 or in Table 5 FLOATING ROOF MATERIALS (See API RP 2003 and Appendix H for additional information.)</p><p>C.3.15 INLET DIFFUSER Supply inlet diffusers when required in Appendix L Data Sheet. (also see 5.8.11.2)</p><p>H.5.6 INLET DIFFUSER Supply inlet diffusers when required in Appendix L Data Sheet. (also see 5.8.11.2)</p><p>Purchaser shall specify details for inlet diffusers for operational considerations. sized to reduce the inlet velocity to less than 1 m (3 ft) per second during initial fill per API RP 2003. Purchaser shall provide pumping rates and any blending, pigging and recirculation data along with the inlet diameter, for Manufacturer's determination of the diffuser design and size. Internal f loating roof suppliers shall specify details for inlet diffusers for protect ion of the floating roof. </p><p>APPENDIX L—API STD 650 STORAGE TANK DATA SHEET Table 4 Other Tank Appurtenances Schedule*: Include all appurtenances not described elsewhere on the Data Sheet. Consider listing in Table 4 such items as the following: - Ladders - Overflow openings (number and size). See H.5.3. - Circulation vents (number and size). See H.5.2.2. - Pressure-vacuum relief valves (nominal size, model number, etc.). - Free vent/flame arrestor. - Grounding clips (quantity and style) - Inlet Diffusers ( when Purchaser specified, include details or design criteria ) </p><p>Some items require supplemental information, such as reference drawings, model numbers, and other specifications. Provide any supplemental information on Line 23.</p><p>Final View 3.9 inlet diffusers: Internal fill line piping with impingement plate, baffles, slots, or lateral openings. Diffusers limit splashing and misting of product, prevent product impingement on internal components, and disperse gases introduced into the tank. </p><p>Page 2 of 3 5.8.11.2 Inlet diffusers shall be provided when specified by the Purchaser for operational considerations or by the floating roof manufacturer for roof floating protection. Requirements shall be included in the Appendix L Data Sheet in Table 4 OTHER TANK APPURTENANCES* or in Table 5 FLOATING ROOF MATERIALS. </p><p>C.3.15 INLET DIFFUSER Supply inlet diffusers when required in Appendix L Data Sheet. (also see 5.8.11.2)</p><p>H.5.6 INLET DIFFUSER Supply inlet diffusers when required in Appendix L Data Sheet. (also see 5.8.11.2)</p><p>APPENDIX L—API STD 650 STORAGE TANK DATA SHEET Table 4 Other Tank Appurtenances Schedule*: Include all appurtenances not described elsewhere on the Data Sheet. Consider listing in Table 4 such items as the following: - Ladders - Overflow openings (number and size). See H.5.3. - Circulation vents (number and size). See H.5.2.2. - Pressure-vacuum relief valves (nominal size, model number, etc.). - Free vent/flame arrestor. - Grounding clips (quantity and style) - Inlet Diffusers (when Purchaser specified, include details or design criteria) </p><p>Some items require supplemental information, such as reference drawings, model numbers, and other specifications. Provide any supplemental information on Line 23.</p><p>Page 3 of 3</p>