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TMB - Plumbing Engineer - Columns: October 2009: Code Update

International terminology


By Ron George

President, Ron George Design & Consulting Services


I recently made a trip to India to speak at a plumbing conference for the Indian Plumbing Association (IPA). India has been operating without building codes and enforcement, and this has led to inadequate plumbing systems throughout the country.


While there, I noted many plastic piping systems in use. One of the booths I visited during the product show was promoting PVC piping for both hot and cold water. I had a discussion with the piping manufacturer about the prohibition of PVC piping for hot water systems in the model codes in the States. He was concerned because he said they use PVC in a lot of projects in India for hot water. He did say they had a temperature limit of 120 degrees Fahrenheit or 48.89 degrees Celsius.


When there is a major development, typically the engineers would design the building to the codes and standards from European countries or North America. However, the new developments must rely on the abilities of the engineers or contractors to provide a safe plumbing, electrical or structural system. Many areas of the country do not have basic water and sewer services. The lack of basic water and sewer services in many areas has caused many of the people to rely on water in streams and rivers for bathing, washing and drinking. India does not have an official plumbing code adopted by the government. There are no building officials or inspectors, there are no contractor licensing requirements and there are no education programs in place for apprentices. Recently, the International Association of Plumbing and Mechanical Officials (IAPMO) developed a Plumbing Code for India — taking into account that it must be in metric units — and it had a group of people addressing many local issues in the plumbing code. This was a fist step in a long journey to improve the living conditions in India.


During my travels there I noted many people along the roadside brewing tea and coffee. Later, I realized the boiling of the water for tea or coffee sterilized the water and minimized dysentery. Tea was quite popular in India and I surmised the practice probably came from the British occupation of India, which lasted for almost 200 years.


The British occupation also brought roads, railways and modern architecture to India mostly with British or European influence. The British also brought the English language to India. While I was there, I found that a large number of people spoke and understood English. There were many languages and dialects spoken in India. Often, language is one of the identifiers of a person’s ethnic background. There are about 18 official Indian languages. They are: Assamese, Bengali, Gujarati, Hindi, Kannada, Kashmiri, Konkani, Malayalam, Manipuri, Marathi, Nepali, Oriya, Punjabi, Sanskrit, Sindhi, Tamil, Telugu and Urdu. Almost all of these 18 languages include different dialects or variations of that language. Besides these 18 languages, there are other languages that are recognized by the central government, including English, but not as official languages. There are other languages that aren’t recognized by the central government. Some of India’s state boundaries were created based on the boundaries of the main Indian languages, as recognized by the Indian constitution.

India will be an emerging market force in the future. They are projected to surpass China in population by the year 2030. However, the task of modernizing the plumbing for the entire country will be a daunting challenge. India has about one-third the land area of the United States, yet there are currently about four times as many people in India. (U.S. has about 307 million people, India has about 1.2 billion people) 


During the IPA conference there was a panel discussion that included participants from several countries around the world. The panelists each gave a presentation on the “Do’s and Don’t’s for Plumbing Systems.” This was followed by the moderator posting plumbing questions to the panelists on monitors and on projection screens for the more than 800 attendees. The panelists took turns addressing how each issue would be addressed in their country. One of the questions asked of the panelists was to evaluate the drainage systems commonly designed and used in some of the newer developments in India. Several panelists were stumped when some of the terminology was posted in the questions. Apparently there are terms they use that were not familiar to many of the panelists. There also were common terms that meant something different depending on where you are from. The questions began with a statement of how the systems were designed and installed followed by a question of if this was an acceptable plumbing installation in each panelist’s country. The panelists faced a bit of terminology challenge when some of the questions were posted to the panelists for discussion. One of the statements and following questions was worded like this:


Indian Plumbing Design Statement


In India, sanitary drainage installations are usually installed as a two-pipe system with separate soil & waste pipes up to the building sewer. Waste pipes are trapped thrice – at the fixture, fixture outlet pipe then connected to the trapped floor gulley and waste stack, and finally it is connected to an externally trapped gully before the building sewer. The waste pipe system is not vented except in cases of very long branches. Soil and waste stacks are extended to the roof with a vent cowl. Vent stacks are provided to soil waste stacks on buildings taller than three floors.


Question: Is this an acceptable installation? 


There were no drawings accompanying the questions. This had a few people scratching their heads, including me as I turned to the Indian engineer next to me and asked what a gully drain was. The first question was directed to a gentleman from Great Britain who asked the obvious question, “What is a gully drain?” I had never heard of a “gully drain” and I was envisioning something like a trench drain. When it was my turn to address the question, I said the model codes in the United States would probably prohibit multiple trapping because they could become air-bound and provide resistance to flow.

During the discussions, an engineer from India, sitting next to me, sketched a drawing on a napkin of what he called a “gully trap” and the associated piping system. That sketch was worth a thousand words.


To me trapped thrice meant three traps in series that is not allowed in the model codes. The issue of multiple trapping was discussed by others on the panel, but the others were still struggling to understand how the system was piped without a drawing.


One of the Indian civil engineers on the panel explained that the three traps would not air-bind because they were indirectly connected to each gully trap.


What the sketch showed was a fixture similar to a floor drain or floor sink with an auxiliary inlet in the body above the outlet or P-trap. This created an indirect waste or air break connection, but it exposed the entire indirect waste line to the room with the floor drain or gully drain. 


The gully drain (see Figure 1) had a built-in trap that consisted of a removable partition. This would not be permissible according to the model codes in the United States. The following is some code language that would apply in this case.

2009 International Plumbing Code – Section 1002.2 Design of traps.


Fixture traps shall be self-scouring


Fixture traps shall not have interior partitions, except where such traps are integral with the fixture or where such traps are constructed of an approved material that is resistant to corrosion and degradation. Slip joints shall be made with an approved elastomeric gasket and shall be installed only on the trap inlet, trap outlet and within the trap seal.


This above code section appears to prohibit traps that are not self scouring and traps with interior partitions such as the gully traps.


2009 International Plumbing Code — Section 1002.3 —Prohibited traps


The following types of traps are prohibited:


1. Traps that depend on moving parts to maintain the seal.

2. Bell traps.

3. Crown-vented traps.

4. Traps not integral with a fixture and that depend on interior partitions for the seal, except those traps constructed of an approved material that is resistant to corrosion and degradation.

5. “S” traps.

6. Drum traps.


Exception: Drum traps used as solids interceptors and drum traps serving chemical waste systems shall not be prohibited.

The gully trap design is basically a drum trap and appears to be prohibited in accordance with the above code section.

2009 International Plumbing Code — Section 1002.5 Size of fixture traps.


Fixture trap size shall be sufficient to drain the fixture rapidly and not less than the size indicated in Table 709.1.A trap shall not be larger than the drainage pipe into which the trap discharges.


The gully trap body is larger than the pipe size, which would allow the waste to slow down and solids would settle in the drain piping. The above code section appears to not allow the gully trap design in this example.

2009 International Plumbing Code — Section 1002.6 Building traps.


Building (house) traps shall be prohibited, except where local conditions necessitate such traps.


Building traps shall be provided with a cleanout and a relief vent or fresh air intake on the inlet side of the trap. The size of the relief vent or fresh air intake shall not be less than one-half the diameter of the drain to which the relief vent or air intake connects. Such relief vent or fresh air intake shall be carried above grade and shall be terminated in a screened outlet located outside the building.


There did not appear to be any logical reason for the building or house trap or gully trap in the installation that was described.


The Uniform Plumbing Code has the following language addressing traps


2009 Uniform Plumbing Code – Section 1002.0 - Traps Protected by Vent Pipes.


1002.1 Each plumbing fixture trap, except as otherwise provided in this code, shall be protected against siphonage, back-pressure, and air circulation shall be assured throughout all parts of the drainage system by means of a vent pipe installed in accordance with the requirements of this code.


1002.2 Each fixture trap shall have a protecting vent so located that the developed length of the trap arm from the trap weir to the inner edge of the vent shall be within the distance given in Table 10-1, but in no case less than two (2) times the diameter of the trap arm.


The above text from the 2009 Uniform Plumbing Code would require individual vents for each fixture or some form of venting to assure that pressure fluctuations from slugs of water in the drain pipe do not cause the trap to blow out or siphon.


2009 Uniform Plumbing Code — Section 1004.0 - Traps — Prohibited


No form of trap that depends for its seal upon the action of movable parts shall be used. No trap that has concealed interior partitions, except those of plastic, glass, or similar corrosion-resisting material, shall be used. "S" traps, bell traps, and crown-vented traps shall be prohibited. No fixture shall be double trapped. Drum and bottle traps shall be installed only for special conditions. No trap shall be installed without a vent, except as otherwise provided in this code.

The above text from the 2009 Uniform Plumbing Code would prohibit traps with interior partitions, double trapping, drum traps and unvented traps.


To me, a two-pipe sanitary drainage system meant a waste stack and a vent stack. The Indian engineers understood a two-pipe sanitary system to mean two single stack waste systems with no venting except for the stack vent. One stack was for black waste or water closet waste discharge and the other stack as for greywater discharge. The sketch on the napkin cleared up this for me, and one of the other panelists suggested a flip chart for illustrations next time for the panelists and attendees.


Air admittance valves


There was a question asking if they used air admittance valves in Indian plumbing systems, and if they could eliminate the vent through the roof. I mentioned the engineers and installers must follow the limitations of the codes, and the manufacturers’ installation instructions. Most manufacturers require at least one vent through the roof to address positive pressures. The laws of physics will not change when you cross borders, but the codes and laws will likely change.


Water hammer arrestors


Another question asked was why they needed to have water hammer arrestors. Water hammer arrestors are required for quick closing valves (near washing machines and dishwashers) in the Uniform Plumbing Code for India (which is currently a voluntary code).


The concern was the only water hammer manufacturers were in the United States. I suggested they download the Plumbing & Drainage Institutes standard from the Internet for free ( The standard gives water pipe sizing information, water hammer arrestor sizing and placement information, and information on how to build an air chamber that is rechargeable.


Later in the trip. I had the opportunity to visit a construction site and photograph the plumbing installations in a complex that had more than five million square feet under construction in 15 buildings. We drove past at least 100 construction sites for international corporations building high rise offices, hotels and support facilities in the High Tech City area of Hyderabad.


At the conference there were representatives from the Green Plumbers USA, IAPMO, The World Plumbing Council, the Chartered Institute of Plumbing & Heating Engineering in the United Kingdom, and Robert Burgon from Scotland, among many other international dignitaries. I enjoyed the wonderful hospitality and the IPA officials said they will plan to have me back for a full day of seminars during the Plumbex Conference and Exposition in Mumbai next spring, and I am looking forward to it.


Ron George is President of Ron George Design & Consulting Services. He has served as Chairman of the International Residential Plumbing & Mechanical Code Committee. He is active in plumbing code and plumbing product standard development committees with ICC, IAPMO, ASSE, ASME, ISEA and ASTM. His company specializes in plumbing, piping, fire protection and HVAC system design and consulting services. He also provides plumbing and mechanical code consulting services and he provides investigations of mechanical system failures and litigation support. His company also provides 3D cad services and Building Information Modeling (BIM) services.


To contact Ron, e-mail: Web site:


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