Ispel practices for heating systems

The inspection of a plant allows for the identification of critical points that require further investigation or maintenance interventions. Focusing specifically on a single piece of equipment, the internal and external visual inspection can highlight macro defects such as: damage to paint and/or insulation, supports, structures, etc., or indications of damage typical of the service or environment such as: corrosion, formation of oxide scale, or cracks.

The inspection can be performed directly by the technician/inspector using their eyesight with the aid of manual tools such as: calipers, scrapers, hammers, and torches; or indirectly with the aid of video endoscopes, video cameras, or drones.

Ha lo scopo di riportare nel dettaglio l’estensione e la tipologia di controlli non distruttivi da effettuare sui singoli componenti di un attrezzatura in base ai meccanismi di danneggiamento attesi. L’intervallo di ricontrollo sarà funzione dell’estensione e tipologia di controlli (efficacia del controllo).

Mandatory checks on pressure equipment designed under hot viscous flow (creep) conditions, in accordance with ISPESL Circular 48/2003, subsequent guidelines, and UNI/TS 11325-1-2-4-6-8.

Components designed in the creep range, with stress values dependent on time, must be subjected, upon expiry of the theoretical design life (VP), to a series of checks aimed at evaluating the remaining life and the Fitness-For-Service (FFS) for further safe operation of the apparatus or equipment of which they are part.

The assessment of the equipment's condition is carried out based on the results of the following steps, to be executed in order:

* Preliminary Analysis and Assessments that consider the design, the operating history of the equipment, the results of previous inspections, and any incidents and/or repairs.
* Preliminary Calculation of the theoretical life consumption of components subject to creep degradation.
* Definition of the Non-Destructive Testing (NDT) Plan to be performed on components subject to creep, taking into account the preliminary calculation.
* Execution of Non-Destructive Tests and Metallographic Examinations to evaluate the structural integrity, in accordance with the NDT Plan above.
* Execution (if necessary) of Supplementary Destructive Investigations on the material to assess its degradation state.
* Calculation of the Theoretical Life Consumption of components subject to creep degradation, based on the actual conditions highlighted by the controls performed (actual thickness, effective dimensions, corrosion, etc.).
* Final Assessments: The state of degradation of the equipment components and their consumed life fraction must be evaluated in light of the results of all the required analyses for each individual situation, as none of them, taken individually, can be considered exhaustive or conclusive. A congruency analysis between calculation results and inspections must be carried out: any discrepancies between calculation results and inspections must be highlighted, evaluated, and appropriately justified. In light of this analysis, the Designer (PR) must propose an interval for continued operation of the equipment (ref. UNI/TS 11325-4).

### Derogations on Statutory Checks (Integrity and Operation)

Subject: Legislative Decree No. 83 of June 22, 2012 (Law No. 134 of August 7, 2012) – Article 36 "Simplification of compliance for the petroleum sector": periodic requalification frequencies for pressure equipment referred to in Tables A and B of Ministerial Decree D.M. 1 December 2004, n. 329.

Donegani Anticorrosione S.r.l, in collaboration with DEKRA Testing and Certification s.r.l, offers to prepare the necessary documentation to comply with the above regarding the extension of integrity and operating checks.

### First Installation or Commissioning Check (DM 329/04)

Pressure equipment or assemblies are subject to the mandatory first installation or commissioning check only if they are installed and assembled by the user on the plant. The check, carried out at the request of the user company, verifies their correct installation on the plant and, if successful, allows for their commissioning (putting into service).

The declaration of commissioning, to be sent to the INAIL Department geographically competent for the province of installation and to the Local Health Unit (SPSAL/PMIP-ASL), must include:

* List of individual equipment, with respective values for pressure (PS), temperature (T), capacity (V), and operating fluid.
* A technical report, with the plant diagram, detailing the installation and operating conditions, and the safety, protection, and control measures adopted.
* An express declaration, drawn up pursuant to Article 2 of the DPR n. 403/1998 (provisions on substitute declarations) certifying that the installation was carried out in compliance with the instructions in the user manual.
* The report that the verifying body delivers to the company at the end of the check, where prescribed.
* A list of components operating under creep conditions (plastic deformation phenomenon of the material, increasing over time, in the presence of constant stresses) or subjected to low-cycle fatigue (phenomenon of degradation of the material's mechanical strength when subjected to repeated stresses over time).

> Note: Heat generators powered by solid, liquid, or gaseous fuel for central heating systems using pressurized hot water with water temperature not exceeding the boiling temperature at atmospheric pressure, having a global potential of the fireboxes exceeding 35 kW (DM 1/12/1975, art.22), are exempted from the commissioning check (Art. 5 of DM 329/2004 – Exclusions).

Hardness testing is a method used to determine a material's resistance to penetration or indentation by a standardized indenter.

The principle of hardness testing involves creating an indentation on the material's surface using an indenter to which a force is applied.

This determines the resistance offered by one material to being penetrated by another.

By making a micro-indentation on the sample surface over a relatively brief period, hardness testing is often preferred for gaining reasonably reliable indications regarding the tensile strength of materials.

There are various scales used to measure material hardness:

* **Brinell**
* **Vickers**
* **Rockwell**
* **Barcol** or **Shore-D** (for polymeric materials)

Donegani Anticorrosione possesses a wide range of durometers capable of covering the various hardness scales, thanks to the latest generation of portable and manual instruments.

The laboratory is also equipped with an automatic durometer for performing Vickers micro-hardness tests.

Metallographic replication is applicable to all metallic materials.

The technique is based on highlighting the structure of the metal to be analyzed and generating a replica of that structure onto a suitable substrate for subsequent microscopic analysis in a laboratory.

It is used to verify the structural and morphological characteristics of the alloy/metal, as well as any variations due to malfunctions/incidents, or damage resulting from service operation (e.g., CREEP).