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ASTM D7946-14
Standard Test Method for Initial pH (i-pH)-Value of Petroleum Products
STANDARD published on 1.7.2014
The information about the standard:
Designation standards: ASTM D7946-14
Note: WITHDRAWN
Publication date standards: 1.7.2014
SKU: NS-39297
The number of pages: 5
Approximate weight : 15 g (0.03 lbs)
Country: American technical standard
Category: Technical standards ASTM
The category - similar standards:
Annotation of standard text ASTM D7946-14 :
Keywords:
i-pH Value, lubricants, petroleum products, potentiometric, ICS Number Code 75.120 (Hydraulic fluids)
Additional information
| Significance and Use | ||||||
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5.1 New and used petroleum products may contain acidic constituents that are present as additives, degradation products formed during service, such as oxidation products or components formed from combustion gases. The i-pH-value is a measure of the amount of acidic substances and their acidity defined under the conditions of test. The i-pH-value is used as a measure of lubricant degradation in service. 5.2 The corrosiveness of acidic components depends on their concentration and acidity. The i-pH-value is a measure of the amount of dissociated acidic components with the potential of corrosiveness towards metals. 5.3 Since a variety of oxidation and blow-by products contribute to the i-pH-value, this test method cannot be used to predict corrosiveness of oil or blends under service conditions against metallic components. No general correlation is known between i-pH-value and the corrosive tendency of blends or oils toward metals. |
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| 1. Scope | ||||||
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1.1 This test method covers procedures for the determination of initial pH (i-pH) in new and in-service lubricants. Note 1: In new and used oils, the constituents that may be
considered to have characteristics influencing the i-pH value
include organic and inorganic acids, esters, phenolic compounds,
lactones, resins, salts of heavy metals, salts of ammonia and other
weak bases, acid salts of polybasic acids, and addition agents such
as inhibitors and detergents. “Initial” is used to differentiate
from aqueous systems. The analysis is terminated after a defined
time interval whenever equilibrium conditions, as known for pH
measurements in aqueous systems, are not reached (see 3.1.1.2)
1.2 This test method is used to indicate relative changes that occur in oil during use under oxidizing conditions or due to contamination by blow-by gases of combustion processes of biogases regardless of the color or other properties of the in-service lubricants. Although the initial pH is made under definite equilibrium conditions, the test method is not intended to measure an absolute acidic property that can be used to predict performance of oil under service conditions. No general correlation between corrosion of non-ferrous bearing metals and initial pH value is known. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. |
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| 2. Referenced Documents | ||||||
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