These materials have a unique crystalline microstructure and stabilisation package, which provides excellent long-term hydrostatic strength
at high temperatures without the need for cross-linking.
This standardized method of analysis can be employed to estimate via time-temperature superposition the stress level that yields a 50-year lifespan at room temperature, which is referred to as the minimal required strength (MRS) or long-term hydrostatic strength
Material properties test according to ASTM D3350 for density, melt index, flexural modulus, tensile strength at yield, slow crack growth resistance, hydrostatic strength
classification, color and UV stabilization; and
Among the topics are long-term hydrostatic strength
and design of thermoplastic piping compounds, the design and performance of plastic drainage pipes in environmental containment facilities, stress crack protocol for finished product testing of corrugated high-density polyethylene pipe, prospects for plastic tubing to replace cast iron conduit in steam heating systems, and specifying plastic pipes for trenchless applications.
Callaway found it well suited for power plant applications such as ESW pipe systems, which require long-term hydrostatic strength
, resistance to slow crack growth and performance at elevated temperatures such as 176 degrees E
What is said to be the first bimodal MDPE produced in North America is newly available for gas distribution pipe requiring long-term hydrostatic strength
and crack resistance.
This article for the first time focuses on the effect of the PP skin on the structure and properties of the PE pressure core pipe, by examining the density, melting temperature, enthalpy of fusion, overall residual stress, and long-term hydrostatic strength
MRS = minimum required strength (MPa)--the categorized value of the long-term hydrostatic strength
determined in accordance with ISO 9080 and ISO 12162 at a fixed time of 50 years and at a fixed temperature of 20[degrees]C.
7 MI octene copolymer with controlled side-chain distribution that is said to provide excellent ESCR plus very good long-term hydrostatic strength
at high temperature without the need for crosslinking.
Within North America, the long-term hydrostatic strength
(LTHS) determined through this analysis is then categorized into one of a series of hydrostatic design basis or HDB.
Because these PE 100/PE 4710 materials have a hydrostatic design basis (HDB) of 1,000 psi at 140[degrees]F and also have a longterm hydrostatic strength
(LTHS) at 73[degrees]F well above 1,600 psi, it was suggested that for these PE 100/PE 4710 materials, Yankee Gas continue to use an HDB of 1,600 psi for their pressure rating, or NO reduction in pressure rating.
The material boasts significantly improved long-term hydrostatic strength
combined with excellent resistance to slow crack growth and rapid growth propagation when compared with MDPE and HDPE resins currently available for PE pressure-pipe production.