Agenda Item 650-564
Manhole Elevation Options
Rev 3 - 09/07/2004 Ballot for Fall 2004
Page 1 of 6
Agenda Item: 650-564Title: /
Manhole Elevation Options
Date: / July 11, 2003Contact: / Ken Erdmann
1109 W. Main Parkway
Catoosa, OK74015
Ph 918-379-6434
Fax 918-379-6450
Cell 918-640-1511
Purpose: / The purpose of this agenda item is to clarify that a manhole can be placed at alternative elevations as allowed by shell nozzles in Table 3-6. After initial work the scope expanded to correct errors in Figure 3-4a and to make manways and nozzle more interchangeable.
Source: / Inquiry 650-I-38-02.
Revision: / 1
Impact: / This agenda item will allow the conversion of existing manholes to low type elevation without the conversion to a shell nozzle. This will reduce time and cost of repairs and apply rules consistently to nozzles and manholes.
Rationale: / The current standard contains notes under Figure 3-4A to allow manholes to be placed at elevations allowed for nozzles. The current notes may be interpreted as requiring manholes to be upgraded to nozzles in order to use nozzle elevations. This agenda item removes this interpretation.
Existing tanks being repaired are referred to API-650 for shell fitting weld spacing. A common repair involves adding a new bottom into an existing tank in a way that reduces the elevation of each shell fitting above the primary tank bottom. To maintain proper weld spacing as listed in API-650 it is common to convert many shell fittings to low type fittings with a reinforcement plate that extends to the tank bottom. Current Figure 3-4A notes 6 and 7 are interpreted by some to require that manholes be upgraded to a nozzle to utilize the low type elevation listed in Column 9 of Table 3-6.
Manholes are required to meet the same material and reinforcement requirements as shell nozzles. The current standard provides manhole heights to allow ease of entry and exit into the tank. The current manhole elevations are not intended to force more extensive repairs of existing tanks.
Update from Spring 2004 / After further review larger problems with Figure 3-4a were discovered.
Problems with Figure 3-4a -
1)The ID of the manway is shown in the Figure but never defined anywhere.
2)Dp is not shown in the Figure at all but is referenced in Manway section of the standard as being the same as nozzles.
3)DR/2 is shown but DR is not shown.
4)Based on historical standard review, the size of the manway is the ID of the manway but using this makes Note 8 referring to Table 3-6 for reinforcement dimensions incorrect.
In summary, manways historically had their own tables containing all repad dimensions and defining the size of the manway as the ID. After the 8th edition these tables were deleted and the reinforcement dimensions were referred to the nozzle Table 3-6. The manway Figure 3-4a now contains a dimension labeled as ID which is not defined anywhere. Also, the hole for a manway is larger than for a nozzle so all repad dimensions given for nozzles are too small to provide reinforcement without participation of the neck.
Approach Approved in Spring 2004:
1)Add OD label to Column 1 of Table 3-5.
2)Fix Figure 3-4a by labeling the manway OD, DR and Dp.
3)Change Figure 3-4a Note 6 to refer to Figure 3-5 not Table 3-6.
4)Change Figure 3-4a Note 7 to allow lower manway elevations as allowed by Table 3-6 and Figure 3-22 when approved by the purchaser.
5)Change Figure 3-4a Note 8 to add OD to the dimensions given in Table 3-6 and to refer to Table 3-7 Column 3 for Dp.
6)Label Column 2 of Table 3-6 as OD.
7)Add “Manhole or” to the LTR-N definition in Figure 3-22.
Refer to the proposed changes below :
Proposed Changes:
Agenda Item 650-564
Manhole Elevation Options
Rev 3 - 09/07/2004 Ballot for Fall 2004
Page 1 of 6
Current API-65010th Ed. 3rd Add.
Existing Table 3-5:
Excerpt From Existing Figure 3-4A:
Proposed
Proposed Table 3-5:
Proposed Figure 3-4A:
Current API-65010th Ed. 3rd Add.
Excerpts from Current Figure 3-4A:
Current Figure 3-4A Notes 6-8:
Proposed
Proposed Figure 3-4A:
Proposed Figure 3-4A Notes 6-8:
6. The shell nozzles shown in Figure 3-5 may be substituted for manholes.
7. The minimum centerline elevations allowed by Table 3-6 and Figure 3-22 may be used when approved by the purchaser.
8. For dimensions OD, DR, DO, L and W, see Table 3-6 Columns 2, 4, 5 and 6. For Dimension DP see Table 3-7 Column 3.
Current API-65010th Ed. 3rd Add.
Current Table 3-6
Current Figure 3-22
Proposed
ProposedTable 3-6
ProposedFigure 3-22
Agenda Item 650-564
Manhole Elevation Options
Rev 3 - 09/07/2004 Ballot for Fall 2004
Page 1 of 6
Summary of previous work on Agenda Item 650-524:
Rev. 01, 07/11/03
The only comment was to clarify that reinforcement area must be checked. Bhana Mistry pointed out that in some cases using a manway from the manway table at a low type elevation from the nozzle table may result in requiring the use of neck material to have enough reinforcement. If you have high strength shell and low strength neck material this could be a problem. The reference to 3.7.2 identifies that reinforcement must be met in place of simply pulling number out of the two tables.
Rev. 02, 09/12/2003
Doug Miller / Larry Hiner commented that they wanted statement that standard elevation was preferred and lower elevations must be agreed upon by purchaser and manufacturer. Also wanted low elevations list that would meet reinforcement. Changes were made.
Richard Whipple was concerned about meeting reinforcement. Changes made will meet reinforcement.
Steve Adolphsen made numerous comments. Has not commented on latest changes at time of meeting.
John Lieb commented to leave note 7 alone but to add comment on reinforcement. Has not commented on latest changes.
Propose that latest changes be re-balloted since Figure 3-4A is being changed to show low type elevation that differ from Table 3-6.
Rev. 03, Spring 2004
Change in approach to make nozzle size the OD so that all dimensions already referenced to Table 3-6 will work. Also, this makes the lower elevation option interchangeable if approved by the purchaser. Sub Group Design gave approval to reballot with new approach.