National Fire Protection Association. 1 Batterymarch Park, Quincy, MA Phone: Fax:

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1 National Fire Protection Association 1 Batterymarch Park, Quincy, MA Phone: Fax: M E M O R A N D U M TO: FROM: NFPA Technical Committee on Water Tanks Elena Carroll, Administrator, Technical Projects DATE: August 18, 2011 SUBJECT: NFPA 22 ROP TC Letter Ballot (F2012) The ROP letter ballot for NFPA 22 is attached. The ballot is for formally voting on whether or not you concur with the committee s actions on the proposals. Reasons must accompany all negative and abstention ballots. Please do not vote negatively because of editorial errors. However, please bring such errors to my attention for action. Please complete and return your ballot as soon as possible but no later than Thursday, September 8, As noted on the ballot form, please return the ballot to Elena Carroll either via to ecarroll@nfpa.org or via fax to You may also mail your ballot to the attention of Elena Carroll at NFPA, 1 Batterymarch Park, Quincy, MA The return of ballots is required by the Regulations Governing Committee Projects. Attachments: Proposals Letter Ballot

2 22-1 Log #CP1 Technical Committee on Water Tanks, Review entire document to: 1) Update any extracted material by preparing separate proposals to do so, and 2) review and update references to other organizations documents, by preparing proposal(s) as required. To conform to the NFPA Regulations Governing Committee Projects. Update all referenced publications to the most recent editions. ****Insert Include 22-LCP1_CA **** 22-2 Log #CP7 Technical Committee on Water Tanks, 1.2 Purpose. The purpose of this standard is to provide a basis for the design, construction, operation, and maintenance of water tanks for private fire protection. Nothing in this standard shall prevent the use of systems, methods, or devices that are equivalent in quality, strength, fire resistance, effectiveness, and durability to those prescribed by this standard, provided technical documentation is made available to the authority having jurisdiction that demonstrates equivalency and the system, method, or device is appropriate for the intended purpose. The text has been removed and is covered in section Log #9 Kenneth E. Isman, National Fire Sprinkler Association, Inc. Add new text to read as follows: Insert new sections and as follows: Bladder Tanks Not Within NFPA 22 Scope. The following types of bladder tanks are not required to meet NFPA 22: (1) Listed bladder tanks used as surge suppressers on the discharge side of fire pumps installed in accordance with NFPA 20. (2) Listed bladder tanks used as expansion tanks for antifreeze sprinkler systems installed in accordance with NFPA 13. (3) Bladder tanks used as foam concentrate tanks installed in accordance with NFPA 16 or NFPA Bladder Tanks Within the Scope of NFPA 22. Bladder tanks shall be permitted to be a part of the water supply for a fire protection system when they meet the requirements of pressure tanks of this standard. The standard is currently silent on the issue of bladder tanks. There are many different types of bladder tanks used in the fire protection industry. Our intent is not to disturb the current practice of using bladder tanks in a variety of ways that do not technically meet NFPA 22. But for those circumstances where the bladder tank is used as a part of the water supply for a sprinkler (or other fire protection system), the tank needs to be pressurized and should be treated like a pressure tank. 1

3 Reference Publication Year in Code Title Change Most Recent Publication Year NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA ACI ACI 350R ANSI SI IEEE/ ASTM S API 5LC ASHRAE ASME Boiler and Pressure Vessel Code ASTM A 6/ A 6M ASTM A 27/ A 27M ASTM A 36/ A 36M ASTM A ASTM A 105/ A105M ASTM A ASTM A ASTM A 131/ A 131M ASTM A ASTM A 181/ A 181M ASTM A 283/ A 283M ASTM A 285/ A 285M ASTM A ASTM A ASTM A 516/ A 516M ASTM A 572/ A 572M ASTM A 615/ A 615M ASTM A 668/ A 668M ASTM A 675/ A 675M ASTM A 992/ A 992M ASTM A ASTM C NFPA 22 Log #CP1 CA F2012 ROP

4 ASTM C ASTM D ASTM D ASTM D ASTM D ASTM D Standard Specifications of the American Wood Preservers Association by the Empty-Cell Process AWS A AWS D AWWA C AWWA D AWWA D AWWA D AWWA D AWWA D AWWA D NWTI Bulletin S SSPC SSPC SP SSPC SP SSPC SP Merriam-Webster's Collegiate Dictionary NFPA 22 Log #CP1 CA F2012 ROP

5 22-4 Log #25 Update referenced AWWA standards to latest editions: AWWA C AWWA D (2011 edition currently in pre-publication phase) AWWA D (2011 edition currently in pre-publication phase) AWWA D AWWA D AWWA D Referenced AWWA standards have been update to comply with applicable new codes and regulations. Update referenced AWWA standards to latest editions: AWWA C AWWA D AWWA D AWWA D AWWA D AWWA D Revised to reference the newest editions, which have been formally accepted by the AWWA Log #22 Technical Committee on Fire Pumps, Add new text to read as follows: A tank providing suction to a fire pump whose capacity is less than the fire protection demand (flow rate times flow duration). Resequence existing Section Guidance for designing break tanks is needed in NFPA 22. This definition is part of the submittal for design guidelines. This submittal to NFPA 22 was accepted by the NFPA 20 committee at the January 2011 ROP meeting in Orlando. This comment was balloted through the Technical Committee on Fire Pumps with the following results: 30 Members Eligible to Vote 5 Not Returned (J. Beals, D. Haagensen, J. McGrath, J. Roberts, and H. Stewart) 25 Affirmative on All 0 Negatives 0 Abstentions 2

6 22-7 Log #18 Kenneth E. Isman, National Fire Sprinkler Association, Inc. New text to read as follows: Add a new definition for suction tank as follows: Suction Tank. Any tank that provides water to a fire pump. The term suction tank is used throughout the standard (section and Table (c) to show a few examples) but is not defined. Although the term is understood by people that know the industry, codes and standards should not rely on such understanding Log #CP8 Technical Committee on Water Tanks, Add new definition as follows: A large diameter shaft that surrounds and encloses the piping below an elevated gravity tank to provide a measure of insulation and protection. Change the term " " to " " throughout the entire document. The committee believes that there is potential confusion over the term "riser" as used in NFPA 13 and NFPA 22. The committee has redefined the term "riser" to "tank riser" to maintain terminology separation and clarity. For consistency the term will be revised throughout the document. 3

7 22-8 Log #23 Technical Committee on Fire Pumps, Insert new Section 4.2. The size and elevation of the tank shall be determined by conditions at each individual property after due consideration of all factors involved. Wherever possible, standard sizes of tanks and heights of towers shall be as specified in 5.1.3, 6.1.2, 8.1.3, and Section 9.2. For suction tanks, the net capacity shall be the number of U.S. gallons (cubic meters) between the inlet of the overflow and the level of the vortex plate. A tank shall be sized so that the stored supply plus reliable automatic refill shall be sufficient to meet the demand placed upon it for the design duration. A break tank shall be sized for a minimum duration of 15 minutes with the fire pump operating at 150 percent of rated capacity. The adequacy and dependability of the liquid source for filling the are of primary importance and shall be fully determined, with due allowance for its reliability in the future. Any source of water that is adequate in quality, quantity, pressure, and reliability to fill the tank in accordance with this standard shall be permitted. Where the water supply from a public service main is not adequate in quality, quantity, or pressure, an alternative water source shall be provided. The adequacy of the liquid supply shall be determined and evaluated prior to the specification and installation of the tank. Resequence Existing Section Guidance for designing break tanks is needed in NFPA 22. This definition is part of the submittal for design guidelines. This submittal to NFPA 22 was accepted by the NFPA 20 committee at the January 2011 ROP meeting in Orlando. This comment was balloted through the Technical Committee on Fire Pumps with the following results 30 Members Eligible to Vote 5 Not Returned (J. Beals, D. Haagensen, J. McGrath, J. Roberts, and H. Stewart) 25 Affirmative on All 0 Negatives 0 Abstentions Insert new Section 4.2. The size and elevation of the tank shall be determined by conditions at each individual property after due consideration of all factors involved. Wherever possible, standard sizes of tanks and heights of towers shall be as specified in 5.1.3, 6.1.2, 8.1.3, and Section 9.2. For suction tanks, the net capacity shall be the number of U.S. gallons (cubic meters) between the inlet of the overflow and the level of the vortex plate. A tank shall be sized so that the stored supply plus reliable automatic refill shall be sufficient to meet the demand placed upon it for the design duration. A break tank shall be sized for a minimum duration of 15 minutes with the fire pump operating at 150 percent of rated capacity. The adequacy and dependability of the water source for filling the tank are of primary importance and shall be fully determined, with due allowance for its reliability in the future. Any source of water that is adequate in quality, quantity, pressure, and reliability to fill the tank in accordance with this standard shall be permitted. Where the water supply from a public service main is not adequate in quality, quantity, or pressure, an 4

8 alternative water source shall be provided. The adequacy of the water supply shall be determined and evaluated prior to the specification and installation of the tank. Resequence Existing Section NFPA 22 pertains only to water tanks and not to storage of other liquids Log #26 Delete the language 'and heights of towers'. The referenced sections don't address heights of towers. See Committee Proposal (Log #CP9) Log #CP9 Technical Committee on Water Tanks, Wherever possible, standard sizes of tanks and heights of towers shall be as specified in 5.1.3, 6.1.2, 8.1.3, and Section 9.2 and The standard sizes for concrete tanks should also be referenced here in Chapter Log #27 Revise this section to provide specific distances required to be considered not subject to fire exposure or provide reference to another standard that does provide specific direction. The location of tanks shall be such that the tank and structure are not subject to fire exposure. It is unclear how to identify what distance constitutes 'not subject to fire exposure'. The location of tanks shall be such that the tank and structure are protected from not subject to fire exposure in accordance with through The subsections provide the manner by which the tank shall be protected from fire exposure Log #28 Coordinate the language of Sec and to eliminate the contradictory language by stating something like Except as provided in , the location of tanks " This section allows tanks to be subject to fire exposure contradicting Sec that prohibits locations where the tank would be subject to fire exposure. Which requirement applies? The language is not contradictory. See Committee Action on Proposal (Log #270). 5

9 22-13 Log #13 Kenneth E. Isman, National Fire Sprinkler Association, Inc. Revise section by inserting the words, supporting tanks so that the sentence reads, Fireproofing, where necessary, shall be provided for steelwork supporting tanks within 20 ft... The proposed additional words are necessary to show that the steel of the tank itself is not required to be fireproofed. Only the support structure is required to be protected from fire exposure Log #29 Revise this section to identify specific conditions for which the manufacturer must provide systems or features not described in NFPA 22. This section requires: In addition to complying with the requirements of this standard, it is expected that the manufacturers of approved structures will also follow the spirit of the standard, by using their experience and ability to create structures that prove reliable under specified conditions. As written, the language does not provide specific requirements which can lead to conflict between contractor, owner and AHJ. Are there sections of NFPA 22 that do not include sufficient requirements such that the manufacturer would be expected to provide designs, details or methods in excess of the requirements of NFPA 22? Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee Log #31 Revise the requirement by deleting the words where a balcony is omitted. This section requires inspection to include a check of the appearance of welding in tank plates where a balcony is omitted. Is the appearance of welding really important if the balcony is omitted? Is there an acceptance criteria for 'appearance' or do we just comment that the welding may be of unsightly or unacceptable appearance? 6

10 22-16 Log #30 Delete the requirement for measuring the extent of inaccessible dents. This section requires the inspection to include the extent of inaccessible dents. If the dents are inaccessible how is the extent of the dents to be determined? The inspection shall include, but shall not be limited to, a check of the following: (1) The thickness of butt-welded plates in tanks and tubular columns (2) The appearance of welding in tank plates where a balcony is omitted and in tubular columns and at struts, except near the ladder and base of the structure (3) The extent of inaccessible dents and out-of-roundness of tubular columns and struts The committee agrees with the submitter's point. Specific text was not provided Log #6 Jon Nisja, Northcentral Regional Fire Code Development Committee Alter section 4.8 as follows: To prevent lightning damage to tanks, protection shall be installed in accordance with Section 4.4 of NFPA 780. Section 4.4 of NFPA 780 is a very small part of the Standard that deals with mechanical damage or displacement only. There are numerous references throughout 780 dealing with lightening protection in tanks and 4.4 is not the only reference. If the intent is to require lightning protection, NFPA 780 should be referenced in its entirety Log #32 Revise the reference section of NFPA 780 to Sec This section requires lightning protection in accordance with Sec. 4.4 of NFPA 780. See Committee Action on Proposal (Log# 6). The committee believes that NFPA 780, Standard for the Installation of Lightning Protection Systems, should be referenced in its entirety Log #33 Revise this section by adding specific acceptance criteria or tolerances. This section requires that workmanship be of such quality that defects or injuries are not produced during manufacture or erection. What constitutes a defect if dents and out of roundness are acceptable (as identified in inspection per )? Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee 7

11 22-20 Log #34 Revise the language of Sec in conjunction with Sec to eliminate the contradictory requirements. This section requires the when the roof is essentially airtight, there shall be a substantial vent above the maximum water level. Sec requires that the roof fit tightly to the top of the tank to prevent the circulation of air over the surface of the water. See Committee Action on Proposal (Log# 52) Log #35 Revise this section by deleting the end of the sentence beginning with to minimize the risk If necessary, move language to the Annex. This section states Where dual service is specified and where local health departments require screening vents against insects, a non-metallic screen or special fail-safe vent shall be provided to minimize the risk in the event that the screens frost over. How does a non-metallic screen minimize risk in the event that the screens frost over? Where dual service is specified and where local health departments require screening vents against insects, a nonmetallic screen or special fail-safe vent shall be provided to minimize the risk in the event that the insect screens occlude frost over. The committee agrees that the use of non-metallic screens does not minimize the risk of the screen occluding Log #36 Replace 'roof vent' with 'vent fan'. This section requires that a roof vent be attached to a flanged neck prior to entering the tank. If a vent would suffice, then the cover of the flanged neck could just be removed to provide the same natural ventilation provided by a vent. It seems that the intention was to add a fan to the flanged neck to provide forced ventilation. 8

12 22-23 Log #37 Revise this section to reference AWWA D100 for limitations on plate thickness. Under AWWA D100, ASTM A283 Gr A is only allowed for non-structural components, Gr B and Gr C are limited to 1 in. for shell plates and Gr D is limited to 3/4 in. for shell plates. API 650 has similar limitations. Under NFPA 22, no restrictions apply. Plate materials shall be of open-hearth, electric furnace, or basic oxygen process steel that conforms to AWWA D100 and one of the following ASTM specifications: (1) ASTM A 36/A 36M (2) ASTM A 283/A 283M, Grades A, B, C, and D The committee agrees with the submitter's substantiation. Specific text was not provided Log #38 Revise this section to read ' that complies with one of the following ASTM specifications " As written, this sections requires plates to comply with all referenced specifications, which they will not. See Committee Action on Proposal (Log# 37) Log #39 Revise this section with limitations on plate thickness or delete this material option. ASTM A285 specification includes grades A, B and C with minimum published yield strengths ranging from 24,000 psi to 30,000 psi. ASTM A285 material is not allowed by under AWWA D100 requirements and API 650 (for oil tanks) only allows grade C for thickness not over 1 inch. ASTM A283 specification is limited in thickness and application in both AWWA D100 and API 650. See Committee Action on Proposal (Log# 37). By referencing AWWA D100, this section does not need to be revised Log #40 ASTM A20 should be referenced for these. ASTM A6 is not applicable to ASTM A516 and ASTM A285 plate. Plates shall be furnished, based on weight, with permissible underrun and overrun in accordance with the tolerance table for plates ordered to weight in ASTM A 620. The committee agrees with the submitter's substantiation. Specific text was not provided. 9

13 22-27 Log #41 Revise this section to reference ASTM F1554 or reference AWWA D100 requirements. ASTM A307 no longer includes anchor bolts (Grade C). The 2007 edition was revised to delete ASTM A307 Grade C (anchor bolts) and all related references to anchor bolts and reference made to ASTM F1554 Gr 36 instead. ASTM A307 Gr A and B do not cover anchor bolt specifications. Bolts and anchor bolts shall conform to AWWA D100 ASTM A 307, Grade A or Grade B. The committee agrees with the submitter's substantiation. Specific text was not provided Log #42 Revise this section to specifically allowable the stress increase per AWWA D100. Section prescribes earthquake resistance per D100. Under AWWA D100, seismic design would include a 1/3 increase in allowable stress. The increase in allowable stress is specified by reference to AWWA D Log #43 Revised Sec. 5.4 to indicate Table 5.4 values plus the increase per , if applicable. This section states that stress produced by specified loads, including seismic loads, shall not exceed the values listed in Table 5.4. This does not allow the 1/3 increase indicated by Sec Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee Log #91 Revise the table to include an allowable for A36, the common steel grade in use today with a published minimum yield strength, Fy, of 36,000 psi. The allowable stress value for tension on net section of rolled steel does not reflect the current requirements in AWWA D100 that address different classes of steels based on their minimum published yield strength. The allowable tension stress in Table 5.4 appears to be based on outdated requirements that did not consider Class 2 materials. The older requirements were based on 0.50Fy and considered that the commonly used material had a published minimum yield strength, Fy, of 30,000 psi. The committee agrees with the submitter. However, the proposal did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee Projects. The committee will form a task group to modify Table 5.4 at the comment stage. 10

14 22-31 Log #92 Revise the table name or change the table contents to only include bending allowables. The title of Table 5.4 indicates that only bending stresses are included in the table. The table includes values for other types of stresses (the first two entries are for direct tension stress, not tension due to bending). See Committee Action on Proposal (Log #91) Log #93 Add a section referencing AWWA D100 for allowable anchor bolt stresses for load cases including seismic loads. The allowable tension stress for anchor bolts is very low compared with other industry tank standards such as AWWA D100 or API 650 resulting in anchor bolts substantially larger than normal. See Committee Action on Proposal (Log #91) Log #94 Revise the table values for anchor bolts to reflect current design practices of AWWA D100-05, Table 5. AWWA D100 provides allowable stresses for several different material specifications and grades of anchor bolts. Also, the allowable stresses for anchor bolts subject to seismic loading are higher than shown in Table 15.4, even if the one-third allowable stress increase is applied. The allowable stress levels in Table 5.4 appear to be based on outdated AWWA D100 requirements. See Committee Action on Proposal (Log #91) Log #95 Revise this table with a footnote that the allowable stress on anchor bolts is based on the area at the root of the threads. The allowable tension stress for anchor bolts does not indicate to which area they must be applied: root area, tensile stress area, gross area. AWWA D100 requires the anchor bolts to be designed based on the root area of the threaded portion. See Committee Action on Proposal (Log #91). 11

15 22-35 Log #96 Revise the formulas for compressive allowable. ***Insert Artwork (Table 5.4) Here*** The table inaccurately displays the values for compression on extreme fibers of rolled sections, plate girders and built-up members. See Committee Action on Proposal (Log #91) Log #44 Revise this section by adding the following sentence: The minimum thickness shall apply to the order thickness, regardless of thickness under-run allowed in the material specification. This section requires that the minimum thickness of tubular columns and struts shall be 1 / 4 in. of 1/4 in. The current text is clear as written. The committee's intent is to require a minimum thickness Log #45 Revise Section as follows: "Except for cylindrical shell plates in contact with water, the minimum thickness of..." This section contradicts with respect to minimum thickness. The committee disagrees that there is a conflict between and , since does not specify any minimum thickness that is less than 1/4 in Log #97 Revise the table to indicate the intended transition point or revise Bottom rings to Bottom ring. What is meant by the following terms: - Bottom rings (does this mean all rings below the top ring or all rings below mid height of the shell?) - Upper rings (does this mean all rings above the bottom ring or all rings above mid height of the shell?) Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee 12

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17 22-39 Log #46 Revise Section as follows: "Except for tubular sections, the sections shall be..." This section requires tubular sections to be hermetically sealed. If they are hermetically sealed tubular sections, then they cannot be open sections as required by Except for hermetically-sealed tubular sections, the sections shall be open to facilitate cleaning and painting. Tubular sections used for columns on elevated legged tanks shall be hermetically sealed to prevent internal corrosion. Not all tubular sections are hermetically sealed Log #47 Revise this section by specifying the salt concentration and the types of salt intended to be covered. This section includes requirements for tanks that are to contain salt. How much salt must be present to be considered a tank that is to contain salt? Does this requirement apply to table salt or sea salt only, or does it apply to other salts as well? Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee Log #48 Revise this section by specifying the salt concentration above which the corrosion allowance applies. This section includes requirements for tanks that are to contain salt. Was this intended to mean tanks that are to contain salt water? If so, is there a minimum concentration at which the corrosion allowance applies? Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee 13

18 22-42 Log #49 Revise this section by specifying the ph range(s) for which the corrosion allowance applies. This section includes corrosion allowance requirements for tanks that are to contain alkaline water. If the ph of the water exceeds 7 it is considered alkaline, even if it is only 7.1. For purposes of this requirement for corrosion allowance, there must be a ph level at which the water is to be considered alkaline and a corrosion problem. Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee Log #50 Revise this section to include the 1/3 increase in allowable stress for load cases including seismic loads (per Sec or AWWA D100). (see also related comment on Sec. 5.4). This section allows tank design in accordance with AWWA D100, Sec. 14. Under AWWA D100 Sec. 14 design, a 1/3 increase in allowable stresses would apply for the seismic load case. Does the 1/3 increase in allowable stress provided in AWWA D100 apply for this case? If this option is not selected, does the 1/3 increase in allowable stress of Sec apply for the seismic load case? Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee Log #51 Revise the language to reference AWWA D100 requirements for allowable local buckling stress; or Revise to say the selected plate thickness shall comply with the allowable local buckling provide allowable local buckling stresses of this standard. And then add provisions for allowable local buckling stresses. This section includes a requirement that in cases where compressive stresses exist, the selected plate thickness shall prevent local buckling. The design requirements cannot prevent local buckling, but we can design within the allowable local buckling stresses to achieve the recommended strength for buckling resistance. Where compressive stresses exist, the selected plate thickness shall prevent local buckling in accordance with AWWA D100. The committee agrees with the submitter's substantiation, but specific text was not provided. Between the options proposed by the submitter, the committee prefers to reference AWWA D

19 22-45 Log #53 Delete this exception or rewrite this section in conjunction with Sec This requirement ( ) shall not apply to plate thicknesses calculated in accordance with Sec Based on review of the standard, it appears that all tank plates must be calculated in accordance with Sec , so this exception means that it does apply to any tank plates. Delete Section The committee agrees with the submitter's recommendation to remove Log #54 Revise this section to read: The longitudinal joints in adjacent circumferential courses shall be staggered or shall be aligned. The entire Chapter 5 is for welded steel tanks. Submitter did not provide a technical justification Log #55 Because applies to all tank plates, delete Sec and all subsections or rewrite the exception to match the intent. Permission to use 4-way junctions shall not apply to plate thicknesses in accordance with Sec Based on review of the standard, it appears that all tank plates addresses in Sec must be calculated in accordance with Sec , so it appears that Sec negates the validity of Sec. 5.8 Delete section The committee agrees with the submitter and chooses to delete the section Log #1 Steven Adolphsen, CBI Services Revise text as follows: The roof purlin depth shall NOT be less than 1/30 of the span length. Limiting depth causes purlins to be springy and adds to ponding on roof due to mid span deflection. If lateral stability is of concern, then specify bracing (we use 12.5' max). See Committee Action on Proposal (Log #CP2). 15

20 22-49 Log #56 Revise the term 'shall' should be 'may' allowing rafters to be less than L/30 rather than requiring it, or Revise the term shall to shall not if it is intended to require stiffer roofs for NFPA 22 tanks than would otherwise be provided for AWWA D100 water tanks. This requirement is an inadvertent error when updating from earlier editions of AWWA and AISC requirements. Under the 1955 edition of AWWA D100, based on the then applicable AISC specifications for design of structural steel (June 1949 edition), D100 included an exception to the requirements of the AISC rules. The AISC specification at that time required that the depth of roof purlins be no less than 1/30 of the span. AWWA D100 then required design in accordance with the AISC specification except that the minimum depth of roof rafters may be less than 1/30 of the span. Later editions of the AISC specification eliminated the minimum depth of members support roofs. AWWA D100 requirements continued to carry the exception until the 1973 edition, where the exception was only allowed as long as the design roof pitch was at least 3/4 :12 in order to minimize ponding. Then, in the 2005 edition, AWWA D100 was revised to require a minimum roof slope of ¾:12, therefore the reference to minimum depth has been deleted. It appears that at some point, the NFPA standard decided to revise the language from may be less than 1/30 of the span length to shall be less than 1/30 of the span length, but failed to realize that the language in AWWA D100 was stated as may be less because it was an exception to the AISC requirement. So, when the language in NFPA 22 was revised, may should have changed to shall not. As stated in the current standard, this requires rafters of relatively short depth which produces springy roof structures with more deflection. The current AWWA D100 requires a minimum roof slope of ¾:12, therefore the reference to minimum depth has been deleted. See Committee Action on Proposal (Log #CP2) Log #CP2 Technical Committee on Water Tanks, Delete Section This section is being removed for compatibility with AWWA D

21 22-51 Log #57 Revise Sec to only apply to elevated tanks as follows: For elevated tanks, plates shall be Add a new section to 5.6 referencing erection tolerances from AWWA D100 as follows: Tanks shall meet the erection tolerance requirements of AWWA D100. Current industry standards only require rolling of shell plates for elevated steel tanks. Also, under AWWA D100, all tanks must meet specific erection tolerances to confirm validity of design for compressive loads Log #52 Delete this section or rewrite to coordinate with Sec It seems that prevent circulation of air over the surface of the water prevents open vents above the top capacity line which conflicts with Sec that requires a vent. The roof shall fit tightly to the top of the tank to prevent the circulation of air over the surface of the water shell to eliminate any gap between the roof and the shell. The revised text clarifies the intent of the section Log #58 Delete the words: to prevent the circulation of air over the surface of the water.' Roof fitted tight to the top of the tank does not prevent the circulation of air over the surface of the water. Which is the requirement: roof fitted tight to the top of the tank or prevention of air circulation of the surface of the water? Why is this required? See Committee Action on Proposal (Log# 52). 17

22 22-54 Log #59 Revise this section to reference that the sand base shall conform to the requirements of AWWA D100 as follows: The sand pad, including ph range of the lime sand mix, sulfate content and chloride content shall meet the requirements of AWWA D100. This section requires a lime treatment of the undertank sand pad to achieve a ph between 6.5 and 7.5 and limits the chloride content to 300 ppm and the sulfate content to 1000 ppm. For corrosion protection of the underside of the tank bottom, AWWA D100 requires limits on chlorides of 200 ppm and sulfates of 100 ppm and, if the sand is treated with lime, a minimum ph of 10.5 for the lime sand mix. Are the higher limits of chlorides and sulfates and low ph range required by NFPA 22 based on testing or research or is this requirement a holdover from previous editions? Log #60 Revise the language by deleting the reference to the inside ladder being located at the second hatch and adding language that an inside ladder be provided for access to the tank floor. Sections , and contain the following requirements: - An easily accessible roof hatch shall be provided. - A second roof hatch shall be place 180 from the existing roof hatch with a ladder to access the tank floor. - Outside and inside steel ladders that are arranged for convenient passage from one to the other and through the roof hatch shall be provided. From these requirements, the inside ladder will be 180 apart from the outside ladder since the outside ladder will provide easy access to the first hatch, and the inside ladder is located at the second hatch. ***Insert Figure Here*** A second roof hatch shall be placed 180 degrees from the primary existing roof hatch with a ladder to access the tank floor Outside and inside steel ladders that are arranged for convenient passage from one to the other and through the primary roof hatch shall be provided. Revise Fig B.1(I) to show secondary roof hatch 180 deg from primary roof hatch. Delete the centerline of the hatch. ***INSERT 22- (Log# 60)-CA. FIGURE B1(I).*** HERE The revised language clarifies the committee's intent that a second interior ladder is not required. The purpose of the second roof hatch is for ventilation. 18

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25 22-56 Log #61 Revise section to read: All outside ladders shall be Section addresses Outside Fixed Shell and Roof Ladder. The text is located under the Outside Ladder section Log #62 Except for the underside of the floor on ground-supported flat-bottom tanks, interior dry surfaces of single pedestal tanks, and faying surfaces of bolted joints that prohibit coatings, parts that are inaccessible after fabrication shall be protected by paint before assembly. Clarify but that are subject to corrosion - Does this mean only interior parts exposed to the stored water or vapor zone? - Does it include exterior weather exposed parts? - Is it only intended to exclude parts such is inside dry surfaces (pedestal tanks) or inaccessible parts that are hermetically sealed from the water, water vapor, or weather? Except for the underside of the floor on ground-supported flat-bottom tanks, parts that are inaccessible after fabrication, but that are subject to corrosion, shall be protected by paint before assembly. The rejected parts of the proposal are covered under the definition of parts that are inaccessible after fabrication Log #63 Revise this section to state either protected by primer or protected by full coating system This section requires that parts that are inaccessible after fabrication, but that are subject to corrosion, shall be protected by paint before assembly. It is unclear whether protected by paint means primed and finish coated or whether the primer coat of paint is sufficient. The intent of the standard is not to dictate how many coats of paint are required to protect steel. It is up to the purchaser to determine. 19

26 22-59 Log #64 Revise the language to clarify that this requirement does not apply to the underside of tank bottoms that are covered by Section This section as written does not exclude applicability to underside of tank bottoms. See Committee Action on Proposal (Log# 62) Log #65 Delete this section. We haven t used riveted tank construction for sixty of seventy years and this requirement is in the section for welded steel tanks, so I have no clue what is intended by this requirement. It is improbable that suitable welding procedure specifications can be developed to weld a joint that includes oil or lacquer on the surfaces contained inside the joint such as contact surfaces between two members being completely welded together Log #66 Revise this section by deleting the words:, or pickling in accordance with SSPC SP 8, SSPC SP8 may not give suitable profile for adhesion of coatings. Most coating systems today require a surface profile not achievable by pickling Log #67 Revise the section to address the following items: 1. Allow weld margins on components to be welded together in the field after being primed in the shop. 2. Not require coatings on faying surfaces of structural bolted joints that prohibit coatings. None given. The submitter did not provide specific language or technical substantiation. 20

27 22-63 Log #68 Revise this section by deleting the words:, or pickling in accordance with SSPC SP 8, SSPC SP8 may not give suitable profile for adhesion of coatings. Most coating systems today require a surface profile not achievable by pickling Log #69 Revise the section to address the following items: Delete the words lead-free. This requirement is covered by Sec Revise the language to clearly not require priming on the underside of the floor unless Sec applies. Revise to allow weld margins on components to be welded together in the field after being primed in the shop All exterior surfaces and inside dry surfaces (pedestal tanks) shall be cleaned by commercial blasting in accordance with SSPC SP 6, or pickling in accordance with SSPC SP 8, and shall be primed with one coated of lead-free alkyd in accordance with the requirements of for Outside Paint System No. 1 of AWWA D102. The committee removed the words "lead free" and added language to coincide with AWWA D Log #70 Revise the language to clearly not require priming on the underside of the floor unless Sec applies. None given. See Committee Action on Proposal (Log# 62) Log #71 Revise the section to include unprimed surfaces as follows: After construction, all weld seams, unprimed surfaces, and any areas " As written, this section implies that the tank components must be primed prior to erection even though Sec and do not require that After construction, all weld seams, unprimed margins, or and any areas where the primer (if preprimed) has been damaged shall be blast-cleaned and patch-primed with the same primer. The revised text removes the implication that all components must be shop primed. 21

28 22-67 Log #72 Revise to read interior surfaces (exposed to stored water or the vapor zone) (See also comment related to Sec ) This section provides requirements for finish coats of interior surfaces exposed to stored water, but fails to include those interior surfaces exposed to the vapor zone. Revise text to read as follows; All finish coat painting for interior surfaces (exposed to stored water) shall be in accordance with the requirements for Inside Paint System No. 1 of AWWA D102., using the same basic system throughout. The intent of the standard is not to limit the use of only one AWWA D102 system Log #73 Revise this section to allow different AWWA D102 Inside Coating Systems to be used for the surfaces above and below the top capacity level. Depending on the details of roof constructions utilized, it is sometimes desirable to utilize a different interior coating system. If Sec is intended to apply to all interior surfaces (not only immersion surfaces), then it does not allow a different coating system for the roof surfaces? See Committee Action on Proposal (Log #72) Log #74 This is not good practice. Add the language or the vapor zone into Sec The finish coats for interior surfaces exposed to stored water are required to comply with AWWA D102 Inside Coating System No. 1 per Sec Because section does not include the language interior surfaces (exposed to stored water or the vapor zone), the interior surfaces above the top capacity level would fall under Sec and be finish coated with an exterior coating system. Finish coat painting for all exterior and interior surfaces not exposed to stored water shall be in accordance with the requirements for Outside Paint System No. 1 of AWWA D102., using two coats of aluminum or alkyd enamel in a color, as specified by the purchaser, to provide a minimum total system dry (not exposed to stored water) film thickness of 3.5 mils (0.09 mm) for aluminum finishes and 4.5 mils (0.1 mm) for alkyd enamels. The intent of the standard is not to limit the use of only one AWWA D102 system. 22

29 22-70 Log #75 Delete the words not exposed to stored water. In this sentence, dry applies to dry film thickness, not to surfaces not exposed to the water or the weather. See Committee Action on Proposal (Log# 74) Log #76 Since the reader must go to the AWWA standard for requirements of the coating systems, revise this section by deleting the end of the sentence beginning with the words, to provide a minimum total system dry The coating system specifications in AWWA D are different than those in AWWA D Outside Coating System No.1 still defines and alkyd coating system with an option for a four-coat system and an option for aluminum finish coats, but now adds an option silicone alkyd finish coat. The total dry film thickness for each coating system option varies, but they do not match those specified in Sec See Committee Action on Proposal (Log# 74) Log #77 Delete Sec This section states 'As provided for in Outside Paint System No. 4 ', but Sec states that coatings shall be per OCS-1. Outside system No. 4 in the 1997 edition of AWWA D102 described a vinyl coating system that would not generally be compatible over an alkyd primer. AWWA D no longer includes a vinyl system. Sec and Sec allow for other systems to be used, so this section is not necessary. 23

30 22-73 Log #78 Revise to read as follows: With approval of the authority having jurisdiction, other finish coats shall be permitted to be used where they are compatible with the selected primer, comply with AWWA D102, and are approved by the authority having jurisdiction. This section allows other finish coats (excluding Inside Coating System No. 5) to be used with approval of the AHJ. This allows finish coats to be used that may not be compatible with the prime coats. Also, current editions of AWWA D100 no longer include coal tar coating system (in AWWA D102-06, ICS-5 is now a zinc rich primer / epoxy / epoxy coating system). See Committee Action on Proposal (Log #CP3) Log #CP3 Technical Committee on Water Tanks, Delete section The standard does not want to refer to coating systems individually. The intent is to reference AWWA D102 in its entirety. 24

31 22-75 Log #20 Kenneth E. Isman, National Fire Sprinkler Association, Inc. Revise Section and add an annex note as follows: Pressure tanks shall be kept with a supply of water to meet the flow and duration demands of the fire protection system as calculated in Chapter 14 of NFPA 13, for the duration required by Chapter 11 of NFPA 13. The quantity of air in the tank and pressure shall be sufficient to push all of the water out of the tank while maintaining the necessary residual pressure required by Chapter 14 of NFPA 13 at the top of the system. Where otherwise approved by the authority having jurisdiction, this requirement shall not apply. Pressure tanks must contain a volume of air, that when pressurized, pushes the water out of the tank (see Figure A ). The larger the quantity of air, the less pressure is necessary to push the water out of the tank. To size a pressure tank properly for a hydraulically calculated fire sprinkler system, determine where you are going to locate the tank, calculate the demand of the fire protection system to the discharge flange of the tank, and then select a volume of tank larger than what is needed to meet the flow and duration demand of the fire protection system. Next, calculate the pressure necessary to push the water out of the tank and maintain the pressure demand in the fire protection system. If the pressure necessary to hold in the tank is higher than the pressure rating of the fire protection system components, select a larger tank. Finally, convey to the owner the ratio of water to air that must be kept in the tank and the minimum tank pressure for maintenance purposes. A formula that can be used for determining the pressure at which the tank needs to be held is: P i = (P f + 15)/A 15 Where P i = tank pressure P f = pressure demand of the fire protection system calculated to the discharge flange of the tank A = percentage of the volume of the tank set aside for air, expressed as a decimal (for example 50% would be expressed as 0.5 ) For example, consider a light hazard sprinkler system with a duration demand of 30 minutes and a demand of 125 gpm at 55 psi calculated to the discharge flange of the tank. If a 5000 gallon tank was used and filled 75% with water, this would meet the 3750 gallon duration demand of the sprinkler system ( = 3750). The remaining 25% of the volume of the tank would be available for air and the tank would need to be pressurized to 265 psi as calculated below: P i = (P f + 15)/A 15 = ( )/ = 265 Clearly this pressure is too high for a sprinkler system where most of the components are rated for a maximum of 175 psi. Unless high pressure rated components are going to be used, a larger thank should be considered. For this same sprinkler system, a 7,000 gallon tank could be used and filled with 3750 gallons of water (54% water and 46% air). This tank would only need to be pressurized to 137 psi, calculated as follows: P i = (P f + 15)/A 15 = ( )/ = 137 This would clearly be a better selection of a tank for this fire protection system. Note that the owner will need to know where the 3750 gallon fill point of the tank is. If the tank is overfilled, then the quantity of air will be decreased and the pressure of 137 will be insufficient to push the water out of the tank at the proper pressure. Tanks above fire protection systems have the advantage of needing less pressure because the water will gain pressure as it drops out of the tank. However, putting tanks above the fire protection system is not always possible. Tanks in basements will work fine if the pressure is calculated correctly. ***Insert 22_L20_Fig A _Rec here*** The pressure tank chapter permits pressure tanks to be used for all kinds of fire protection systems, but only references NFPA 13 in the sizing situation. This is because NFPA 13 is the only document with good information on sizing and calculating the pressure for the tank. Rather than reference NFPA 13, it would be better to put this information in NFPA 22 directly. Since the information keeps moving in NFPA 13, the chapter references become obsolete anyway. 25

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33 22-76 Log #21 Kenneth E. Isman, National Fire Sprinkler Association, Inc. Delete text to read as follows: Delete the sentence that is currently and all of Section Renumber existing as a new so that all that is left of is the following: Subject to the approval of the authority having jurisdiction, tanks shall be permitted to be buried in accordance with the requirements of There is no reason to require tanks to be above the top level of sprinklers and there is no reason to require special permission of the AHJ to put tanks in the basement or anywhere below the top level of sprinklers. The formula used by NFPA 13 to size tanks and determine pressure (and proposed for NFPA 22 in our previous proposal) adjusts for the elevation pressure situation by forcing a higher pressure for the tanks below the activating sprinklers/nozzles Log #CP10 Technical Committee on Water Tanks, A listed horizontal bronze-seat swing-check valve and an renewable-disc globe indicating control valve shall be provided in the horizontal position in the pipe near the tank The globe indicating control valve shall be placed between the check valve and the tank. The language indicates the modern practice Log #79 Revise sections , , , and to provide consistent, unambiguous requirements that are not contradictory with each other. Section requires the tank to be set on a compacted crushed stone or granular base or on concrete foundations. Then, Sec requires a 3 in. layer of clean dry sand be laid on the compacted grade, but does not indicate to which of the types of foundations addressed in Sec this will apply. Projects. Submitter did not provide specific text, per 4.3.3(c) of the Regulations Governing Committee 26