# PSC 134.21 Heating values and specific gravity.

**Citation:** Wis. Admin. Code § PSC 134.21  
**Type / status:** regulation / current  
**Agency:** Public Service Commission of Wisconsin  
**Effective:** 1959-03-01  
**Published:** Not stated

Complete current PSC 134.21 from official Wisconsin Legislature sources (gas-utility-service).

## Document text

PSC 134.21 Heating values and specific gravity.

(1) Each utility which is furnishing gas service shall have on file with this commission for each municipality served the heating value, specific gravity, and composition of each type of gas regularly supplied and also for the gas which may be used for standby purposes and the range of values for peak shaving. The heating value filed shall be the total heating value with the indication whether it is on a wet or dry basis. (See definitions in s. PSC 134.02.)

(2) All gases whether the regular gas supply, a mixture of gases or a substitute gas used for peak shaving purposes shall operate properly in normal gas utilization equipment. Where used for emergency or standby, the gas shall operate reasonably well in such equipment. (The customer requiring gas of a particular chemical composition shall make such arrangements as may be required to protect against damage by reason of change in composition.)

(3) The monthly average heating value of the gases as delivered to the customers in any service area shall not be less than the heating value standard on file with this commission and the heating value at any time at constant specific gravity shall not be more than 5% above or 4% below this standard. At constant heating value, the specific gravity of the gas shall not vary more than 10% from the standards filed with the commission. If the heating value is varied by a greater amount than specified, the specific gravity shall be varied in such a way that the gas will operate satisfactorily in the customer’s utilization equipment. Customers using processes that may be affected by a change in the chemical composition of the gas shall be notified of changes. Agreements with such customers shall specify the allowable variation in composition.

(4) For required periodic heating value tests see s. PSC 134.25. The specific gravity of the gas shall be determined at least once each month when there is no change in the type or sources of gas and when there is a change in the type of gas. Whenever emergency or peak shaving plants are ran or when mixed gases are used, daily determinations of specific gravity shall be made.

## Provenance

- Official: Yes
- Source: <https://docs.legis.wisconsin.gov/document/administrativecode/PSC%20134.21>
- Source ID: `wi-legislature-pipeline-corpus`
- SHA-256: `f5900905b0aef9a6d6519248ffecd7eee64c2c6d098fa44de9136f5fa267c5e4`
- Retrieved: 2026-08-12T06:25:04.554Z
- Exported: 2026-08-23T08:09:00.573Z
- Document slug: `wi-psc-134-21`

### Source metadata

```json
{
  "jurisdiction": "US-WI",
  "code": "Wisconsin Administrative Code",
  "chapter": "PSC 134",
  "section": "PSC 134.21",
  "category": "gas-utility-service",
  "currentThrough": "2026-08-01",
  "currentnessBasis": "Official publisher states the entire administrative code is current and updated on the first day of each month.",
  "legalScope": "This completeness-verified corpus contains every current section of Wisconsin Administrative Code Chapters PSC 133, 134, and 135, plus complete Wis. Stat. §§ 196.745 and 182.0175. Chapter PSC 135 is the dedicated gas-safety chapter. Chapters PSC 133 and 134 are included because the Wisconsin PSC identifies all three chapters as requirements used in pipeline-safety inspections; they also contain broader construction, siting, utility-service, billing, metering, and customer provisions.",
  "applicabilityCaveat": "Applicability depends on Wisconsin PSC jurisdiction, operator and facility type, intrastate or interstate status, gas-public-utility status, project thresholds, activity, exemptions, waivers, Commission orders, federal preemption, and the specific provision. Wis. Stat. § 196.745 excludes propane distribution systems from the PSC pipeline-safety program, while the one-call law reaches transmission facilities beyond natural-gas pipelines.",
  "incorporationCaveat": "Chapter PSC 135 adopts and supplements federal minimum pipeline-safety standards, principally 49 CFR Parts 191, 192, 193, and 199. The source also cites statutes, administrative rules, Commission forms and orders, and private technical standards. References are retained as metadata; incorporated material is not reproduced and its edition, legal effect, and licensing must be verified at the referenced source.",
  "rightsCaveat": "Official Wisconsin Legislature and Public Service Commission text is preserved with attribution and source hashes. Public availability does not establish a blanket license for site presentation, agency marks, annotations, forms, or incorporated federal and privately authored standards; downstream redistribution requires separate rights review.",
  "history": "History: Cr. Register, February, 1959. No. 38, eff. 3-1-59.",
  "references": [
    {
      "citation": "PSC 134.02",
      "referenceType": "wisconsin-administrative-code",
      "url": "https://docs.legis.wisconsin.gov/document/administrativecode/PSC%20134.02",
      "linkBasis": "official-publisher-supplied exact-citation link"
    },
    {
      "citation": "PSC 134.25",
      "referenceType": "wisconsin-administrative-code",
      "url": "https://docs.legis.wisconsin.gov/document/administrativecode/PSC%20134.25",
      "linkBasis": "official-publisher-supplied exact-citation link"
    },
    {
      "citation": "Register, February, 1959",
      "referenceType": "administrative-register",
      "url": "https://docs.legis.wisconsin.gov/document/register/1959/B/toc",
      "linkBasis": "official-publisher-supplied exact-citation link"
    }
  ],
  "sourceCollection": "wi-legislature-psc-code",
  "region": "WI"
}
```