Q/A about Bryan Hauger Consulting 30 minute free consultation
Clients often ask us, "What kinds of questions can your plastic consultants answer in just 30 minutes?" To help answer that question, we've pulled a number of actual questions and answers from previous Q&A sessions. Still have some unanswered questions? Please contact us for a free 30 minute consultation so we can provide you with answers!
Pre-compounded Pipe Materials and Black Masterbatch
Q - Is it possible to produce pipe by adding black masterbatch with carbon black to natural resin in plant in accordance with the requirements in ASTM D2513-14e1, Section 4 and ASTM D3035-15, Section 5?
A - ISO 4427 requires the use of pre-compounded materials in the manufacturing of polyethylene (PE) pipe for water applications. The ASTM standards you have noted do not include a specific requirement to use pre-compounded materials and are therefore permissive of either pre-compounded materials or in-plant blending of natural resin with colorant compound. These standards are potentially less clear than they could be because they do not explicitly state that both methods of providing a fully compounded black pipe product are allowed. For a more complete discussion of the allowable use of in-plant blending, I would like to direct you to the September 2014, 70-page paper I prepared for the Electric Power Research Institute, which can be found as the first link on this page. Specifically, you can read section 4 which deals with this subject in some detail. Here is an excerpt from that report.
“Thus far, this Section has focused on either unpigmented polyethylene or the black polyethylene compound that is converted into HDPE pipes. Although some resin manufacturers provide polyethylene compound with carbon black already added, commonly called pre-compounded polyethylene compound, others provide natural resin and a resin that contains carbon black at levels significantly higher than 2.0 to 3.0 weight per cent. The resin manufacturer provides the pipe manufacturer with instructions for combining the two materials, the natural resin and the black pigment concentrate compound, often referred to as “salt and pepper” compounding. The instructions provided will likely include important manufacturing details such as the blending ratios of the two components, instructions for proper drying techniques for the pigment concentrate compound and information regarding the details of mixing and extrusion used to create desirable properties in finished HDPE pipes”.
Q - Is it possible to produce pipe by adding black masterbatch with carbon black to natural resin in plant in accordance with the requirements in ASTM D2513-14e1, Section 4 and ASTM D3035-15, Section 5?
A - ISO 4427 requires the use of pre-compounded materials in the manufacturing of polyethylene (PE) pipe for water applications. The ASTM standards you have noted do not include a specific requirement to use pre-compounded materials and are therefore permissive of either pre-compounded materials or in-plant blending of natural resin with colorant compound. These standards are potentially less clear than they could be because they do not explicitly state that both methods of providing a fully compounded black pipe product are allowed. For a more complete discussion of the allowable use of in-plant blending, I would like to direct you to the September 2014, 70-page paper I prepared for the Electric Power Research Institute, which can be found as the first link on this page. Specifically, you can read section 4 which deals with this subject in some detail. Here is an excerpt from that report.
“Thus far, this Section has focused on either unpigmented polyethylene or the black polyethylene compound that is converted into HDPE pipes. Although some resin manufacturers provide polyethylene compound with carbon black already added, commonly called pre-compounded polyethylene compound, others provide natural resin and a resin that contains carbon black at levels significantly higher than 2.0 to 3.0 weight per cent. The resin manufacturer provides the pipe manufacturer with instructions for combining the two materials, the natural resin and the black pigment concentrate compound, often referred to as “salt and pepper” compounding. The instructions provided will likely include important manufacturing details such as the blending ratios of the two components, instructions for proper drying techniques for the pigment concentrate compound and information regarding the details of mixing and extrusion used to create desirable properties in finished HDPE pipes”.
Natural Gas Distribution System Construction and ASTM F2817
Q- Could you tell us the reason for the prohibition of PVC for new natural gas pipeline construction in ASTM F2817?
A - A few years ago ASTM D2513 was separated into many separate parts based on materials in order to produce a D2513 standard that contained only polyethylene materials. Such a standard would facilitate regulatory approval and adoption of standard by PHMSA and USDOT into 49 CFR Part 192. A version of D2513 without the other materials could be simply and clearly examined for alignment and acceptability with the Federal gas code for polyethylene materials in the United States. Similarly, the removal any language regarding new gas installations for PVC reflects a change that PHSMA put into the US code of construction a long time ago – perhaps even decades ago – to eliminate new gas pipeline construction using PVC. This is not to say that a properly constructed uPVC can’t function effectively in natural gas pipelines. Rather, this position reflects that there were more issues per mile with uPVC than with polyethylene. Therefore, a strong preference for PE installations caused the regulator to remove the approval for new construction using uPVC but did not justify the immediate replacement of all existing PVC gas installations. Your question points out that there is a continuing need for guidance from ASTM International as to International standard methods of natural gas infrastructure construction. A project is possible to revise ASTM F2817 to include new construction within the scope of the standard. If you need an ASTM citation to support new construction using PVC, then you would probably want to use a version of D2513 that is sufficiently old that it still included PVC for new installations. ASTM sells D2513-87 on their website at https://www.astm.org/DATABASE.CART/HISTORICAL/D2513-87.htm. Of course, I must include the precautionary note that I will not accept any liability associated with the above discussion. It is absolutely essential and mandatory that you rely on your own engineering judgement as to risks and mitigations regarding any natural gas applications involving plastic piping.
Q- Could you tell us the reason for the prohibition of PVC for new natural gas pipeline construction in ASTM F2817?
A - A few years ago ASTM D2513 was separated into many separate parts based on materials in order to produce a D2513 standard that contained only polyethylene materials. Such a standard would facilitate regulatory approval and adoption of standard by PHMSA and USDOT into 49 CFR Part 192. A version of D2513 without the other materials could be simply and clearly examined for alignment and acceptability with the Federal gas code for polyethylene materials in the United States. Similarly, the removal any language regarding new gas installations for PVC reflects a change that PHSMA put into the US code of construction a long time ago – perhaps even decades ago – to eliminate new gas pipeline construction using PVC. This is not to say that a properly constructed uPVC can’t function effectively in natural gas pipelines. Rather, this position reflects that there were more issues per mile with uPVC than with polyethylene. Therefore, a strong preference for PE installations caused the regulator to remove the approval for new construction using uPVC but did not justify the immediate replacement of all existing PVC gas installations. Your question points out that there is a continuing need for guidance from ASTM International as to International standard methods of natural gas infrastructure construction. A project is possible to revise ASTM F2817 to include new construction within the scope of the standard. If you need an ASTM citation to support new construction using PVC, then you would probably want to use a version of D2513 that is sufficiently old that it still included PVC for new installations. ASTM sells D2513-87 on their website at https://www.astm.org/DATABASE.CART/HISTORICAL/D2513-87.htm. Of course, I must include the precautionary note that I will not accept any liability associated with the above discussion. It is absolutely essential and mandatory that you rely on your own engineering judgement as to risks and mitigations regarding any natural gas applications involving plastic piping.
© Copyright Bryan Hauger Consulting, Inc., 2014 - 2018. All rights reserved.
