1、 Standard Practice Inspection, Cleaning, and Remediation Technology for Water Piping in Buildings This NACE International standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone, wh
2、ether he or she has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE standard is to be construed as granting any right, by implication or otherwise, to manufacture
3、, sell, or use in connection with any method, apparatus, or product covered by letters patent, or as indemnifying or protecting anyone against liability for infringement of letters patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use o
4、f better procedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this standard in specific instances. NACE assumes no responsibility for the interpretation or use of this standard by other part
5、ies and accepts responsibility for only those official NACE interpretations issued by NACE in accordance with its governing procedures and policies which preclude the issuance of interpretations by individual volunteers. Users of this NACE standard are responsible for reviewing appropriate health, s
6、afety, environmental, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE standard may not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/
7、or operations detailed or referred to within this standard. Users of this NACE standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any exist
8、ing applicable regulatory requirements prior to the use of this standard. CAUTIONARY NOTICE: NACE standards are subject to periodic review, and may be revised or withdrawn at any time in accordance with NACE technical committee procedures. NACE requires that action be taken to reaffirm, revise, or w
9、ithdraw this standard no later than five years from the date of initial publication and subsequently from the date of each reaffirmation or revision. The user is cautioned to obtain the latest edition. Purchasers of NACE standards may receive current information on all standards and other NACE publi
10、cations by contacting the NACE FirstService Department, 15835 Park Ten Place, Houston, TX 77084-5145 (telephone +1 281-228-6200). Approved 2014-06-26 NACE International 15835 Park Ten Place Houston, Texas 77084-5145 +1 281-228-6200 ISBN 1-57590-283-4 2014 NACE International NACE SP0214-2014 Item No.
11、 21176 SP0214-2014 NACE International i _ Foreword This standard presents information and procedures that can be used by owners, managers, or operators of inhabited, nonindustrial buildings to assess the quality of the piping systems and the options available to return the piping systems to a servic
12、eable condition (remediation). The remediation may involve cleaning, piping replacement, or other steps. It is a risk-based approachthe ultimate risk is leakage of the system, system unavailability, or both. The focus of this standard is on the options available and the steps taken when determining
13、whether the risk is acceptable or whether a more cautious remediation program must be selected. The information provided in this standard is based on the understanding that it is economically and physically feasible to remediate the system being evaluated. This standard presents recommendations on h
14、ow to identify the problems, assess their severity, determine an appropriate course of action, and guide the owner through the implementation of that course of action. The delivery of potable water to users, along with the removal of used water products, is also addressed in this standard. Piping sy
15、stems provide an essential function to any buildings operation. Occasionally, these piping systems operate at less than optimum efficiency or fail to operate. The ability of the building to function (i.e., to offer an appropriate operating environment) is fundamental to the economic viability of tha
16、t building. If a piping system fails to operate as it was designed, the building loses its marketability. Maintenance of the operating capability of building piping systems is a task that relies on many individuals. This standard is intended for use by heating plant operators, water treatment provid
17、ers, and those who operate comfort cooling equipment and computer cooling equipment. This standard was prepared by Task Group (TG) 158, “Inspection, Cleaning, and Remediation Techniques for Piping in Buildings.” This TG is administered by Specific Technology Group (STG) 11, “Water Treatment.” This s
18、tandard is issued by NACE under the auspices of STG 11. In NACE standards, the terms shall, must, should, and may are used in accordance with the definitions of these terms in the NACE Publications Style Manual. The terms shall and must are used to state a requirement, and are considered mandatory.
19、The term should is used to state something good and is recommended, but is not considered mandatory. The term may is used to state something considered optional. _ SP0214-2014 ii NACE International _ NACE International Standard Practice Inspection, Cleaning, and Remediation Technology for Water Pipi
20、ng in Buildings Contents 1: General 1 2: Definitions 2 3: Recognizing the Need to Clean .3 4: Defining the Problem .3 5: Inspection and Monitoring Techniques 4 6: Building and System Information . 11 7: Options for Remediating Building Piping Systems . 12 8: Operational Factors that Affect the Choic
21、e of Mitigation Operations . 13 9: Take No Action 14 10: Piping Replacement . 14 11: Mechanical Cleaning 15 12: Online Chemical Cleaning . 16 13: Offline Chemical Cleaning . 16 14: Planning the Remediation Project 19 15: Monitoring and Controlling the Cleaning Process 20 16: Transition to Service 20
22、 References 21 Bibliography . 21 Appendix A: Specification Organizations for Inspection Techniques . 22 _ SP0214-2014 NACE International 1 _ Section 1: General 1.1 Introduction The water-usage systems addressed in this standard are as follows. (Note: this list covers all piping systems in residentia
23、l and office buildings; it is not applicable to industrial facilities.) GROUP I: The predominant water-usage systems in most buildings consisting of potable water (hot and cold); steam and condensate systems; and waters for heating, ventilation, and air conditioning (HVAC) (open and closed systems)
24、GROUP II: Waste watersewage and drainage GROUP III: Higher quality waterspreconditioning systems and boilers GROUP IV: Fire-protection systemswet, dry, foam, and other systems GROUP V: Architectural systemsfountains, waterfalls, and other displays 1.2 Group I: Highest Water-Usage Systems in Building
25、s 1.2.1 The Group I piping systems include the potable-water system and building systems that are major users of potable water. 1.2.2 Potable-water systems are seldom cleaned except when flow conditions or leakage mandate that maintenance be performed. The U.S. Environmental Protection Agency (EPA)(
26、1)requires these systems to be sanitized before being placed back into operation to prevent transmission of disease.11.2.3 Steam systems typically use high-purity water, which ensures long life of the generating equipment or the steam piping systems. The condensate system, however, requires treatmen
27、t to make it less susceptible to corrosion. This piping system usually requires more attention than the steam system. 1.2.4 HVAC systems may be open or closed, depending on the design of the system. Open-condenser water systems usually have a cooling tower and associated highwater usage. Water treat
28、ment programs are critical for open and closed HVAC systems. 1.2.5 Closed systems require little to no make-up water because there is no draining or blow-down. Replacement water is added only when the system is opened or drained for maintenance, or because of unavoidable leakage from components or p
29、iping connectors. Closed heating/cooling systems may require cleaning because of interior fouling. 1.3 Group II: Waste waters and Drain Waters 1.3.1 Wastewater and drain-water systems are almost never chemically treated (except for grease disposal) and are discharged from the building into the local
30、 sewage system for processing. This may be the buildings own leaching field, a local sewer system and water treatment facility, or a major metropolitan wastewater treatment program. It is common practice for hotels and restaurants to chemically treat grease traps and ejector pits. 1.3.2 Wastewater a
31、nd drain water piping systems are rarely cleaned except when the system is inoperative. The cleaning is primarily mechanical, such as high-pressure water washing or mechanical rotor cleaning, if such cleaning is appropriate. 1.4 Group III: Systems Requiring High-Quality Waters Higher-quality water i
32、s required for the operation of some equipment, such as boiler feed water systems. Additional equipment, such as reverse-osmosis (RO) systems or sodium zeolite systems, may be required to condition the water. 1.5 Group IV: Fire-Suppression Water Systems (1)Environmental Protection Agency (EPA), Arie
33、l Rios Building, 1200 Pennsylvania Ave. N.W., Washington, DC 20460. SP0214-2014 2 NACE International 1.5.1 Wet systems are filled and allowed to remain stagnant without circulation and usually without treatment. Recent sprinkler code changes require that where microbiologically influenced corrosion
34、(MIC) concerns are suspected, water treatment chemicals shall be used. 1.5.2 Wet systems are connected to, but isolated from, the main potable water system by means of a backflow prevention device. 1.5.3 Generally, there is no active circulation in the stand pipes, except during testing periods; the
35、re may be limited circulating, charged headers in certain systems. Dry systems are pressurized with air or nitrogen. These systems may be damp because of periodic hydrostatic testing or internal condensation if used outside, where a risk of freezing exists. This interior moisture condition can lead
36、to severe unexpected corrosion problems with leakage occurring from the inside of the pipe. 1.6 Group V: Architectural ApplicationsFountains, Waterfalls, Display Uses These systems are usually open recirculating systems with wide open basins, full-stream filters, and circulating pumps. Piping is mos
37、tly polyvinyl chloride (PVC), although copper and steel pipes are sometimes used. System water is usually accessible to the public for decorative display. It is kept clean with full-stream filtration and intermittent treatment with oxidizing biocide for esthetic purposes. Open areas are mechanically
38、 cleaned on a regular basis. 1.7 Cleaning can only provide clean surfaces, which represent original piping minus the corrosion loss. Lost wall thickness and pipe wall damage from pitting corrosion cannot be restored. 1.8 However, cleaning provides the option of restarting with a deposit-free, clean
39、system that responds to properly treated water by minimizing the corrosion rate. Cleaning has the added benefit of maximizing the life of the remaining pipe. _ Section 2: Definitions Acid: Chemical compound that produces hydrogen (H+) ions replaceable with metal ions in solution. A solution with a p
40、H below the neutral value of 7.0 is considered acidic; this occurs when more H+ions than hydroxide (OH-) ions are present in the solution. Alkaline: Chemical compound that neutralizes acids in solution, and is capable of receiving H+ions from other compounds; solution of soluble salts having a pH gr
41、eater than the neutral value of 7.0. Biocide: Material that exhibits toxicity toward certain bacteria, fungi, molds, or other microbial populations. Blowdown (Bleed off): (1) the injection of air or water under high pressure through a tube to the anode area for the purpose of purging the annular spa
42、ce and possibly correcting high resistance caused by gas blockage (cathodic protection use); (2) the process of discharging a significant portion of the aqueous solution in order to remove accumulated salts, deposits, and other impurities (boiler or cooling water tower use). Boiler: Equipment fired
43、by a direct heat source (such as gas, coal, electricity, or oil) that heats water under pressure to produce steam used for heat, process, or power generation needs. Chelants: Chelants form soluble complexes with certain types of deposits such as iron and copper oxides. Chilled Water: Water cooled in
44、 a chiller and circulated through a converter to produce cool air for building air conditioning systems. Closed Loop (Closed System): System that circulates water for heating or cooling needs that is not open to the atmosphere. A closed loop typically has very low rates of water loss. The system sho
45、uld experience less than 5% of volume loss per year. Condensate: Any gas that is condensed to a liquid state through the release of heat. In building systems, the term is typically used to refer to steam condensed to water at the individual heat load. Because steam condensate normally contains consi
46、derable usable energy and should be very pure, it is recovered and recycled in the boiler loop. Condenser Loop (Open System): System that rejects heat from a chiller by evaporation in a cooling tower. Cooling Tower: Device in which water from a chiller condenser or cooling coils is cooled by atmosph
47、eric evaporation. SP0214-2014 NACE International 3 Corrosion Coupon: A preweighed metallic specimen of a known size and composition that is exposed to an environment for a specific time period to evaluate the corrosive effects of the environment in which it is installed. Couplant: A conductive gel t
48、hat provides good contact between an ultrasonic thickness (UT) sensor and the metal surface. Dead Leg: Any area in a piping system where water can become stagnant and where water is not exchanged during flushing. Head Loss: An increase in differential pressure across a system or portion of a system, often caused by fouling or restrictions in piping. Heat Exchanger: A device in which two mediums of different temperatures exchange heat for the purpose
