Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D2283-86 – Standard Test Method Technical Guide
ASTM D2283 – 86 (Reapproved 1997) provides the definitive specification for askarels—synthetic, fire-resistant chlorinated aromatic hydrocarbon liquids used as insulating and cooling media in liquid-filled transformers. This standard is essential for guiding both the management of legacy PCB-containing fluids and the qualification of modern non-PCB replacement askarels.
📜 Scope and Classification of Askarels
According to Section 1.1, this specification covers synthetic nonflammable electrical insulating liquids of the chlorinated aromatic hydrocarbon-type known as askarels. The standard defines an askarel in Section 3.1.1 as a generic term for a group of synthetic, fire-resistant, chlorinated aromatic hydrocarbons which, under arcing conditions, produce gases consisting predominantly of noncombustible hydrogen chloride.
Table 1 of the standard classifies askarels by component type, although Note 1 clarifies that these compositional groupings are descriptive rather than prescriptive; conformance to the specification is governed by physical and chemical properties. The major classifications are detailed below:
| 🟦 Classification | 📋 Description |
|---|---|
| Types A through G | PCB-type askarels previously available and still in use in the field (Note 2). Manufacture and sale of PCBs is currently prohibited by government regulations (Note 3). |
| Type H | A non-PCB askarel recently introduced as a retrofill and replacement fluid for existing equipment (Note 2). |
⚠️ Regulatory Context: Note 3 of the standard explicitly states that “current governmental regulations prohibit the manufacture and sale of polychlorinated biphenyls (PCBs).” This document thus serves as a reference for evaluating all askarels, whether legacy PCB fluids or new non-PCB formulations.
⚙️ Detailed Requirements and Test Methods
Section 4.1 mandates that all askarels for use in transformers conform strictly to the limits prescribed in Table 2 of the standard. These requirements ensure adequate dielectric strength, thermal stability, and fire resistance. The table below summarizes the core property categories and their associated evaluation standards:
| 🟦 Property Category | 🎯 Specification Guidance | ⚡ Referenced Test Method |
|---|---|---|
| Dielectric Breakdown Voltage | Minimum breakdown voltage per Table 2 | D 877 |
| Dissipation Factor / Resistivity | ≤ 15% at 60 Hz and 100°C (Note 4) | D 924 / D 1169 |
| Specific Gravity | Specified range per Table 2 | D 1810 |
| Water Content | Maximum level per Table 2 | D 1533 |
| Fire Point / Flash Point | Determined by Cleveland Open Cup | D 92 |
| Acidity (Neutralization Number) | Maximum level per Table 2 | D 664 / D 974 |
| Viscosity | Specific limits per Table 2 | D 445 / D 88 |
💡 Technical Equivalency: Note 4 provides important testing flexibility. “A dissipation factor at 60 Hz and 100°C that is not in excess of 15 % shall be considered satisfactory” in place of a direct resistivity measurement. The standard confirms that a strong statistical correlation exists between dissipation factor and resistivity, although other factors modify the precise relationship predicted by theory.
Additional requirements evaluated through this standard include Pour Point (D 97), Refractive Index (D 1218), Coefficient of Thermal Expansion (D 1903), Scavenger Content (D 1701), Inorganic Chlorides (D 1821), and Color (D 2129). Correct execution of sampling per Test Method D 923 (Section 5.1) is critical before any of these evaluations can be performed.
❓ Frequently Asked Questions
🔍 What is an askarel as defined in this standard?
Per Section 3.1.1, an askarel is a generic term for a group of synthetic, fire-resistant, chlorinated aromatic hydrocarbons used as electrical insulating liquids. A defining property is that under arcing conditions, the gases produced consist predominantly of noncombustible hydrogen chloride with only lesser amounts of combustible gases.
💡 How are Types A–G different from Type H?
According to Notes 2 and 3, Types A through G are PCB-type askarels that were previously available and are still in use in the field. Type H is a non-PCB askarel introduced specifically as a retrofill and replacement for these older PCB-containing units.
⚡ What is the specific limit for dissipation factor?
Note 4 specifies that a dissipation factor measured at 60 Hz and 100°C that is not in excess of 15% is considered satisfactory. This