Pre-insulated pipes made of crosslinked polyethylene (PE-Xa) and shaped products for hot water supply networks for Kharkiv

New clarification added: ____ANSWER Part 2____Dear Bidder,Thank you for your question and for your interest in the tender.1. Regarding the Normative Basis (EN 15632-1/2 vs. CEN/TS 17889).The requirement for compliance with EN 15632-1/2 is established as the mandatory technological baseline for the entire pre-insulated system. This standard governs the critical performance of the system as a whole, including the thermal insulation (PUR), the outer casing, and, most importantly, the long-term thermal aging behavior of the bonded structure. The Customer acknowledges that CEN/TS 17889:2024 is a relevant specific document for reinforced thermoplastic pipes (TRSP). However, the current Technical Specification is intentionally formulated to be technology-neutral. The requirement for EN 15632 does not restrict the participation of manufacturers of reinforced pipes; rather, it sets the minimum quality threshold that all buried district heating systems must meet. Bidders are encouraged to provide CEN/TS 17889 certificates or other relevant Test Reports as additional evidence of the carrier pipe's equivalence or superior performance. Important: the presence of a CEN/TS 17889 certificate does not exempt the manufacturer from the obligation to comply with the basic EN 15632. Considering the above, no amendments to the Technical Specification are required, as the "basic minimum" principle already permits such high-performance solutions. 2. Regarding the Oxygen Barrier (Clause 2.2.19).The mention of "EVOH, aluminum or equivalent" is a functional description intended to cover various established technological methods for ensuring oxygen tightness. The Technical Specification does not mandate a specific material but requires a verified performance outcome. If a TRSP construction utilizes an integrated diffusion barrier within its multilayer structure, the Bidder shall demonstrate that this barrier meets the necessary performance criteria defined in the relevant standards. The choice of material remains with the manufacturer, provided the result is equivalent or superior to the required characteristics.3. Regarding Supplementary Standards (ISO 21003).The Technical Specification does not contain a reference to the standard you mentioned.Conclusion: the Technical Specification provides a universal framework based on functional requirements and a verified technological minimum. This approach ensures equal treatment and non-discrimination, as it allows for the submission of various technical models (including TRSP) that meet the project’s high-performance targets. Bidders are expected to demonstrate the compliance and superiority of their specific solutions through comprehensive technical documentation and Test Reports during the bid submission. The Technical Specification remains unchanged.Best regards, Procurement Team

New clarification added: Dear Tender Organizers,During our review of the technical requirements of the tender documentation, we established that certain provisions concerning the regulatory confirmation of the characteristics of flexible pre-insulated pipe systems require clarification and alignment with the currently applicable European normative documents.In its current wording, the technical specification simultaneously refers to standards and design features that belong to different categories of pipe systems. This creates a risk of ambiguous interpretation, complicates the preparation of tender proposals, and may unjustifiably restrict competition among manufacturers whose products comply with current relevant EU standards.In particular, EN 15632-2:2022 establishes requirements and test methods for flexible, factory-made, buried district heating pipe systems with plastic service pipes and is applied together with Part 1. At the same time, CEN/TS 17889:2024 is a separate technical specification for flexible buried district heating pipe systems with thermoplastic reinforced service pipes (TRSP).In view of the above, we kindly request that you consider the following comments and provide an official clarification.1. Regarding Clause 1.9.6 and confirmation of compliance with EN 15632-1:2022 / EN 15632-2:2022Clause 1.9.6 requires the participant to provide a certificate of conformity with EN 15632-1:2022 and EN 15632-2:2022.We note that such requirement is not sufficiently precise where the subject of procurement may include reinforced thermoplastic pipe systems. While EN 15632-2:2022 does regulate flexible pre-insulated buried systems with plastic service pipes, CEN/TS 17889:2024 separately establishes classification, general requirements and test methods specifically for TRSP systems.According to the publicly available description of CEN/TS 17889:2024, this document covers bonded or non-bonded systems consisting of a PE-Xa inner layer, thermoplastic intermediate layer, para-aramid reinforcement layer, outer thermoplastic layer with diffusion barrier, thermal insulation, and PE casing.Therefore, if the subject of procurement in fact includes a reinforced TRSP-type construction, confirmation of compliance exclusively under EN 15632-1:2022 and EN 15632-2:2022 does not ensure full normative coverage of such product type. In such case, CEN/TS 17889:2024 should also be accepted as an appropriate conformity basis. This does not mean that EN 15632 is incorrect as such; however, by itself it is not sufficient for the full regulatory description and assessment of reinforced TRSP construction.Accordingly, we kindly request that Clause 1.9.6 be clarified by:clearly defining whether the procurement concerns an unreinforced polymer service pipe system or also permits reinforced TRSP-type systems; andif reinforced systems are permitted, allowing confirmation of conformity under CEN/TS 17889:2024 or an equivalent document.2. Regarding Clause 2.2.19 and the oxygen barrier requirementClause 2.2.19 states: “Oxygen diffusion barrier: EVOH, aluminum or equivalent.”In our opinion, this wording also requires clarification if the procurement concerns a TRSP-type pipe system.CEN/TS 17889:2024 covers constructions with an outer thermoplastic layer and a diffusion barrier layer within the multilayer reinforced polymer structure. Therefore, where the contracting authority requires or allows a TRSP system within the logic of CEN/TS 17889:2024, the indication of aluminum as an acceptable oxygen barrier material is not fully consistent with the relevant normative approach applicable to such TRSP construction.In other words, one technical model should not simultaneously combine features of different regulatory product-description systems. If a TRSP system under CEN/TS 17889:2024 is procured or permitted, the barrier layer requirements should be formulated within the framework of that specific document. If another polymer or multilayer system is intended, this should be stated directly and unambiguously in the tender documentation.Accordingly, we kindly request that Clause 2.2.19 be revised into a normatively consistent wording, namely:either exclude aluminum as an acceptable oxygen barrier material for TRSP constructions; orclarify separately that another type of pipe system is being procured for which such structure is acceptable.3. Regarding references to EN ISO 21003We also draw attention to the fact that EN ISO 21003-1:2008 applies to multilayer piping systems intended for hot and cold water installations inside buildings. Therefore, this standard concerns internal building systems and is not the relevant core standard for flexible buried district heating systems.For this reason, any reference to EN ISO 21003 may only serve as a supplementary technical argument, but not as the primary normative basis for defining requirements for buried flexible pre-insulated pipes for district heating networks.Accordingly, the key criterion in this procurement should be consistency with the standard governing the declared system type, namely:EN 15632-2:2022 for systems with plastic service pipes; orCEN/TS 17889:2024 for systems with thermoplastic reinforced service pipes (TRSP).4. Practical consequences of the current wordingThe current wording of the technical requirements creates a situation where:participants cannot unambiguously determine which specific pipe construction is expected by the contracting authority;manufacturers of reinforced TRSP systems may be unjustifiably restricted in confirming conformity of their products;tender proposals may be compared across technically different solutions, complicating objective evaluation; andthere is a risk of subjective interpretation during bid assessment and rejection of participants not for technical reasons, but because of unclear wording.In our opinion, in order to ensure transparency, non-discrimination, equal access and equal treatment in evaluation, it is advisable to clearly separate the requirements applicable to unreinforced plastic service pipe systems from those applicable to reinforced TRSP systems, and to align the oxygen barrier requirement with the relevant normative document for the declared product type.5. Request for clarification and amendmentIn view of the above, we kindly request that the contracting authority:bring Clause 1.9.6 into line with the scope of the currently applicable European normative documents;clearly define whether the subject of procurement is an unreinforced polymer system or a reinforced TRSP-type system;if reinforced thermoplastic systems are allowed, permit confirmation of conformity under CEN/TS 17889:2024 or an equivalent normative document;eliminate the inconsistency in Clause 2.2.19 concerning the oxygen barrier material and align it with the relevant standard for the declared pipe system type; andensure overall clarity, consistency and technical coherence of the tender documentation.We kindly ask you to provide an official clarification on the issues raised and, if agreed, to introduce the relevant amendments to the tender documentation.____ANSWER Part 1____Dear Bidder,Due to character limitations in the system, the response will be published in a separate post without duplicating the questions included in this entry.Best regards, Procurement Team

New clarification added: We kindly request the following clarifications and amendments to the tender documentation:In Section A – Summary of Requirements for the Supply of Pre-insulated Pipes made of Crosslinked Polyethylene (PE-Xa) and Shaped Products for Hot Water Supply Networks and Section B – Technical Specifications for Goods – Comparative Data Tables, items 1–5, please remove “fiber-reinforced”, since the tender documentation clearly requires compliance with EN ISO 15875, which does not apply to fiber-reinforced pipes (e.g., Kevlar-reinforced) and applies exclusively to non-reinforced PE-Xa pipes.Additionally, we kindly request to remove “fiber-reinforced” wherever it appears throughout the tender documentation.Please remove PN10, since clause 2.1.4.4 clearly specifies Operating pressure not less than 0.6 MPa (6 bar).Clause 1.9.10 – kindly clarify which specific document is required: please indicate the document name or reference to the applicable regulation.Clause 2.1.4.2 – Application class indicated (according to EN ISO 15875-1): Class 5 – please correct to Class 1a according to Table 1 of ISO 15875-1, since clause 2.1.4.6 of the tender documentation specifies Design operating temperature not less than 60°C, and the tender documentation clearly states that the pipes are intended for hot water supply networks, which corresponds to Class 1a according to Table 1 of ISO 15875-1 (screenshot of the table attached).Clause 2.1.4.7 – Please correct Tmax to 80°C according to Class 1a, Table 1, ISO 15875-1 (currently overstated in the documentation).Clause 2.1.4.8 – Please correct Tmax to 95°C according to Class 1a, Table 1, ISO 15875-1 (currently overstated in the documentation).Clause 2.2.5 – Degree of crosslinking incorrectly specified as not less than 75% – please correct to not less than 70% in accordance with ISO 15875-2 referenced in the tender documentation (screenshot of the table attached)._____ANSWER_____Dear Bidder,Thank you for your question and for your interest in the tender.1. Regarding the removal of "fiber-reinforced".The requirement for the pipe to be fiber-reinforced is a fundamental technical necessity for this project. While EN ISO 15875 defines the requirements for the base PE-Xa material, the addition of a reinforcing layer is essential to ensure the required flexibility and structural integrity of large-diameter pipes while maintaining a high pressure-to-wall-thickness ratio. The technical specification remains unchanged to ensure the reliability of the installation in specific site conditions.2. Regarding the removal of "PN10".The Nominal Pressure (PN) rating is defined at a reference temperature of 20°C. According to the project design and the physical properties of polymer materials, a PN10 rating is required to ensure a safe and continuous operating pressure of at least 0.6 MPa (6 bar) at the project’s maximum operating temperatures. Lowering the nominal class would compromise the safety margin and the calculated service life of the system.3. Regarding Application Classes and Temperature Regimes (Clauses 2.1.4.2, 2.1.4.7, 2.1.4.8).The specified temperature parameters, including a Design Operating Temperature of 60°C, a Maximum Operating Temperature (Tmax) of 90°C, and a Malfunction Temperature (Tmal) of 100°C, are mandatory project design requirements. These values are dictated by the specific technical conditions of the local heat network and are necessary to ensure reliable operation during peak loads or system malfunctions. The equipment must strictly correspond to these design data; therefore, a downgrade to Application Class 1 or 2 is not acceptable.4. Regarding the Degree of Crosslinking (Clause 2.2.5).The requirement for a degree of crosslinking of not less than 75% is established to ensure superior mechanical properties, chemical resistance, and enhanced thermal aging stability of the PE-Xa carrier pipe. While ISO 15875-2 specifies a minimum threshold of 70%, the Customer reserves the right to set higher technical thresholds to ensure a high-quality, safe product with an increased safety margin for critical infrastructure.5. Regarding the "Health Certificate" (Clause 1.9.10).The "Health Certificate" refers to documentation confirming the sanitary and epidemiological safety of the foamed polyurethane insulation. For foreign-manufactured goods, the Customer will accept a Sanitary/Hygienic Certificate issued by the authorized national body of the country of origin, or a Material Safety Data Sheet (MSDS / SDS) that confirms the material is safe for human health and the environment during its intended use.Conclusion: the technical specifications, including material reinforcement, pressure ratings, temperature regimes, and crosslinking requirements, are based on actual engineering designs and calculated load profiles of the network. Consequently, the requested amendments to these parameters are not accepted.Best regards, Procurement Team

New clarification added: Dears in UNOPS Team,Please kindly find our question for the mentioned tender below.1. According to information we received from the manufacturer, they are manufacturing pipes with PEX foam insulation. Can we submit a quotation for PEX foam insulated pipes instead of PUR foam insulated pipes?We are waiting for your valuable reply.Kindly Regards._____ANSWER____Dear Bidder,Thank you for your question and for your interest in the tender.Please be informed that the proposal for pipes with cross-linked polyethylene foam insulation (PEX-foam) is not acceptable. This proposal fails to comply with the Technical Specification for the following reasons:1. Non-compliance with Product Name and General Requirements: The specification explicitly requires the use of polyurethane foam (PUR).2. Non-compliance with Standard: According to Section 2.2, the pipes must comply with EN 15632-2, which sets strict thermal and mechanical requirements for systems with polyurethane foam (PUR) insulation.3. Energy Efficiency: The specification sets a strict thermal conductivity limit of not more than 0.027 W/(m·K) at 50°C. PEX-foam properties significantly exceed this limit (typically >0.038 W/(m·K)), which contradicts the project's objectives for heat loss minimization.4. Environmental Requirements: The specification requires the use of cyclopentane-based foaming technology, which is mandatory for PUR insulation within this procurement.The specification requirements remain unchanged.Best regards, Procurement Team 

New amendment added #1: Please note that the following changes have been made1) The following clauses of Requirements for the supply Pre-insulated pipes made of crosslinked polyethylene (PE-Xa) and shaped products for hot water supply networks have been revised: Clauses 1.1, 1.9.3, 1.9.4, 1.9.5, 1.9.9, 2.2.1, 2.2.15.1, 2.2.15.3, 2.2.19, 2.2.29.4, 2.2.29.5, 2.2.29.7, 2.3.1 and 2.3.2 (details are provided in the uploaded document “Details Rev 1_RFQ/2026/62028”).2) The tender submission deadline has been extended until 20 April 2026 in order to provide potential bidders with sufficient time to prepare their proposals, taking into account the number and scope of the revisions.3) Corresponding amendments have been made to the Checklist and Criteria, particularly with regard to certification requirements.The revised documents have been uploaded:Rev 1_RFQ_2026_62028_Section_III_Returnable Bidding FormsRev 1_RFQ/2026/62028_Section_II_Schedule of Requirements – Supply of pre-insulated plastic pipes and accessoriesKind regards,Procurement Team

New clarification added: UA: Щодо товщини ізоляції для відповідних типів труб:Звертаємо вашу увагу, що вказані у технічному описі комбінації діаметрів труб та товщини ізоляції для відповідних типів труб не відповідають стандартним типорозмірам провідних європейських виробників. Оскільки стандарт EN 15632-2 не встановлює жорсткої єдиної таблиці «обов’язкових діаметрів», просимо, з метою розширення кола учасників та забезпечення конкурентних умов, визначити мінімально допустимі товщини ізоляції для кожного типу труб з допуском по зовнішньому діаметру +1...5 мм.Зокрема, просимо підтвердити можливість пропозиції наступних стандартних європейських типорозмірів (провідна труба / зовнішній діаметр ізоляції):63/ (125÷130) мм75/(140÷145) мм  90/(160÷165) мм  110/(160÷165) мм  125/(180÷185) мм  Збільшена товщина ізоляції при збереженні діаметру труби є технічно кращим рішенням, оскільки це безпосередньо знижує тепловтрати (покращує енергоефективність) та підвищує механічну надійність усієї системи. Враховуючи вищевикладене, просимо дозволити використання таких параметрів.EN: Regarding insulation thickness for the respective pipe types:Please be advised that the combinations of pipe diameters and insulation thicknesses for the respective pipe types specified in the technical description do not align with the standard dimensions of leading European manufacturers. Since the EN 15632-2 standard does not prescribe a mandatory single table of "required diameters," we request, for the purpose of expanding the range of participants and ensuring competitive conditions, that you define the minimum allowable insulation thicknesses for each pipe type with an outer diameter tolerance of +1...5 mm.Specifically, we request confirmation of the acceptability of the following standard European sizes (carrier pipe / outer insulation diameter):63/ (125÷130) мм75/(140÷145) мм  90/(160÷165) мм  110/(160÷165) мм  125/(180÷185) мм   Increased insulation thickness while maintaining the pipe diameter is a technically superior solution, as it directly reduces heat loss (improves energy efficiency) and enhances the mechanical reliability of the entire system. In view of the above, we kindly request you to allow the use of these parameters._____ANSWER____Dear Bidder,Thank you for your question and for your interest in the tender.Please be advised that the diameters specified in the product descriptions (e.g., 75/140) are nominal values (dn). The actual outer diameters of the service pipes and protective casings may have tolerances in accordance with ISO 15875 and EN 15632, respectively. Proposals of the manufacturer's standard sizes corresponding to these nominal values (including those reflecting the design features of the corrugated casing) are acceptable.Best regards, Procurement Team 

New clarification added: UA: Щодо пункту 2.3.1 (Перехідні фітинги): З метою розширення кола потенційних учасників та забезпечення конкурентних умов закупівлі, просимо погодити можливість пропозиції перехідних фітингів PE-Xa на сталь зі зварювальним кінцем, що включають обтискну обійму (компресійний хомут) замість насувної гільзи (sliding sleeve).Даний тип компресійного з'єднання повністю відповідає функціональному призначенню та вимогам стандарту ISO 15875-5 щодо міцності з'єднання на розрив та повної герметичності. Чи підтверджуєте ви можливість пропозиції такого технічного рішення як еквівалента?EN: Regarding Clause 2.3.1 (Transition Fittings): In order to expand the range of potential participants and ensure competitive procurement conditions, we request your approval to propose PE-Xa to steel transition fittings with a weldable end, including a compression ring (clamping sleeve) instead of a sliding sleeve.This type of compression connection fully complies with the functional purpose and requirements of the ISO 15875-5 standard regarding joint pull-out strength and leak-tightness. Could you please confirm if this technical solution is acceptable as an equivalent?_____ANSWER____Dear Bidder,Thank you for your question and for your interest in the tender.We confirm the acceptability of PE-Xa to steel transition fittings using a compression clamp (clamping sleeve) as an equivalent to the sliding sleeve. This solution is acceptable subject to confirmation of full compatibility with the proposed piping system and compliance with EN ISO 15875-5 (specifically for mechanical joints type "M").The bidder must provide, as part of its proposal, documentation confirming leak-tightness, operability under working temperature/pressure conditions, and pull-out resistance. The Technical Specification will be amended to include various types of acceptable jointing methods. The revised clauses will read as follows:2.3.1 "Type: transition fitting PE-Xa to Steel with weldable end, including sliding sleeve or clamping sleeve (compression ring)."2.3.2 "Connection design: mechanical compression connection (axial or bolt-tightened) compatible with PE-Xa SDR 11 pipe series. Goods must be specifically certified/tested for use with the offered fiber-reinforced PE-Xa pipe system."Please monitor the platform for the official publication of the revised documentation.Best regards, Procurement Team 

New clarification added: UA: Щодо пункту 2.2.19 (Кисневий бар’єр): З метою розширення кола учасників та забезпечення найвищої якості обладнання, просимо погодити можливість пропозиції гнучких труб PE-Xa з алюмінієвим (металевим) антидифузійним шаром замість шару EVOH.Алюмінієвий бар’єр забезпечує абсолютну кисневу непроникність 0 мг/м²·д, що значно перевершує вимоги ISO 17455. Дана конструкція є технічно кращою, оскільки створює суцільний металевий захист від корозії, що не залежить від вологості середовища, та додатково армує трубу. Чи підтверджуєте ви можливість пропозиції такого покращеного рішення?Ось переклад технічних переваг українською мовою, адаптований для офіційного листування або тендерної документації:Технічні переваги алюмінієвого бар'єру над шаром EVOH·         кисневий бар'єр: На відміну від полімерного шару EVOH, який лише обмежує дифузію кисню, алюміній створює суцільний фізичний бар'єр. Це забезпечує нульову проникність кисню (0 мг/м²·д), що гарантує 100% захист від корозії дорогих компонентів системи (котлів, теплообмінників) протягом 50-річного терміну служби.·         Незалежність від вологості: Бар'єрні властивості EVOH суттєво погіршуються при контакті з вологою (наприклад, у разі появи конденсату під ізоляцією). Металевий шар зберігає свої характеристики нульової проникності незалежно від вологості навколишнього середовища або стану теплоізоляції.·         Механічне армування: Алюмінієвий шар виступає як конструкційний елемент армування. Він підвищує стійкість труби до стрибків внутрішнього тиску та термічного розширення, роблячи всю систему трубопроводів стабільнішою та надійнішою порівняно зі стандартними пластиковими трубами з покриттям EVOH.·         Стабільність форми та цілісність монтажу: Металевий шар допомагає трубі краще зберігати надану їй форму при вигинах під час монтажу. Це зменшує механічне напруження на з'єднувальні фітинги та спрощує процес прокладання в складних умовах траншеї.·         Довгострокова стабільність матеріалу: У той час як полімерні бар'єри можуть деградувати з часом під постійним впливом високих температур, алюміній незмінно зберігає свої захисні та механічні властивості протягом усього життєвого циклу теплової мережі. EN: Regarding Clause 2.2.19 (Oxygen Diffusion Barrier): In order to expand the range of potential participants and ensure the highest quality of equipment, we request your approval to propose flexible PE-Xa pipes with an aluminum (metallic) anti-diffusion barrier instead of the EVOH layer.The aluminum barrier provides absolute oxygen impermeability of 0 mg/m²·d, which significantly exceeds the requirements of ISO 17455. This design is technically superior as it creates a solid metallic corrosion protection that is independent of ambient humidity and provides additional reinforcement to the pipe. Could you please confirm if this enhanced technical solution is acceptable?_____ANSWER____Dear Bidder,Thank you for your question and for your interest in the tender.The service pipe must be equipped with an effective oxygen diffusion barrier meeting the requirements of ISO 17455. The Technical Specification will been amended to allow various types of anti-diffusion layers (EVOH, aluminum, or equivalent) that provide adequate corrosion protection for the system. The revised clauses will read as follows:1.9.9 "Type Test Report(s) issued by an accredited third-party body. The submitted set of documents must explicitly confirm:- compliance of carrier PE-Xa pipe with standard ISO 15875 (Parts 1 and 2) and fittings with ISO 15875-3;- application class (as per ISO 15875);- oxygen permeability compliance (oxygen diffusion barrier according to ISO 17455)."2.2.19 "Oxygen Diffusion Barrier: The service pipe must have an oxygen diffusion barrier (EVOH, aluminum, or equivalent) that limits oxygen permeability in accordance with ISO 17455. The oxygen permeability at 40°C shall not exceed 0.32 mg/(m²·d). The barrier layer shall be protected against mechanical damage (e.g., located between PE-Xa layers or deeply bonded)."2.2.29.7 "ISO 17455 - oxygen permeability compliance (oxygen diffusion barrier). Compliance must be confirmed in the Type Test Report issued by an accredited third-party body."Please monitor the platform for the official publication of the revised documentation.Best regards, Procurement Team  

New clarification added: UA: Щодо пунктів 2.2.1, 2.2.15.1 та 2.2.15.3 (Матеріал зовнішньої оболонки): З метою розширення кола потенційних учасників та забезпечення конкурентних умов закупівлі, просимо погодити можливість використання для зовнішньої гофрованої оболонки лінійного поліетилену низької щільності (LLD-PE) замість HDPE.Повідомляємо, що LLD-PE забезпечує значно вищу гнучкість трубопроводу, кращу стійкість до розтріскування під напругою (ESCR) та вищу ударну в'язкість при низьких температурах, що є критично важливим для монтажу гнучких систем. Даний матеріал повністю відповідає функціональним вимогам стандарту EN 15632 та або ДСТУ Б В.2.5-31:2007.  EN: Regarding Clauses 2.2.1, 2.2.15.1, and 2.2.15.3 (Outer Casing Material): In order to expand the range of potential participants and ensure competitive procurement conditions, we request your approval to use Linear Low-Density Polyethylene (LLD-PE) for the outer corrugated casing instead of HDPE.Please be advised that LLD-PE provides significantly higher pipe flexibility, superior Environmental Stress Crack Resistance (ESCR), and better impact strength at low temperatures, which is critical for the installation of flexible pipe systems. This material fully complies with the functional requirements of the EN 15632 / ДСТУ Б В.2.5-31:2007 standard.  _____ANSWER____Dear Bidder,Thank you for your question and for your interest in the tender.The material of the outer corrugated casing must comply with the requirements of EN 15632. The Technical Specification will be amended to include various types of Polyethylene (HDPE, LLDPE, or an equivalent with similar or superior physical and mechanical properties as per EN 15632). The revised clauses will read as follows:1.9.7 "Type Test Report(s) issued by an accredited third-party body. The submitted set of documents must explicitly confirm:1) compliance of the complete system with standard EN 15632 (Parts 1 and 2);2) insulation parameters:- initial thermal conductivity (according to ISO 8497 or EN 12667),- density;- cell structure (closed porosity);- water absorption;- mechanical strength properties;- use of cyclopentane-based blowing agent;3) outer casing parameters: carbon black content (as per ISO 6964) and resistance to brittle fracture (as per ISO 974);4) fitting assembly resistance to pull-out forces and leak-tightness."2.2.1 "The pipes shall consist of a fiber-reinforced PE-Xa service pipe, thermal insulation made of polyurethane foam, and a corrugated polyethylene outer casing."2.2.15.1 "Outer casing material: Polyethylene (HDPE, LLDPE or equivalent with similar or superior physical and mechanical properties) complying with EN 15632."2.2.15.3 "Material grade: bimodal polyethylene suitable for use as outer casing of pre-insulated pipe systems in accordance with EN 15632."2.2.29.4 "ISO 6964 - carbon black content in outer casing. Compliance must be confirmed in the Type Test Report issued by an accredited third-party body."2.2.29.5 "ISO 974 - resistance of outer casing to brittle fracture. Compliance must be confirmed in the Type Test Report issued by an accredited third-party body."Please monitor the platform for the official publication of the revised documentation.Best regards, Procurement Team 

New clarification added: UA: Щодо пунктів 1.9.3, 1.9.4 та 1.9.5 (Сертифікати ISO виробника):Звертаємо вашу увагу на технічну неточність у пункті 1.9.5 тендерної документації, де зазначено стандарт ISO 45001:2019. Повідомляємо, що чинна міжнародна версія цього стандарту була прийнята у 2018 році (ISO 45001:2018), а версії 2019 року в міжнародній системі сертифікації не існує.З метою розширення кола потенційних учасників та забезпечення конкурентних умов, просимо підтвердити наступне:1.      Дозволити надання сертифіката ISO 45001:2018 як коректної та чинної версії стандарту.2.      Дозволити надання сертифікатів згідно з національними стандартами України, а саме ДСТУ ISO 9001:2015, ДСТУ ISO 14001:2015 та ДСТУ ISO 45001:2018.Дані національні стандарти України є ідентичними міжнародним (IDT — identical) за змістом та вимогами. Чи підтверджуєте ви можливість надання таких еквівалентних документів згідно з українськими стандартами ДСТУ ISO?EN: Regarding Clauses 1.9.3, 1.9.4, and 1.9.5 (Manufacturer's ISO Certificates):We would like to draw your attention to a technical inaccuracy in Clause 1.9.5 of the tender documentation, which specifies the ISO 45001:2019 standard. Please be advised that the current international version of this standard was released in 2018 (ISO 45001:2018); there is no 2019 version of this standard in the international certification system.In order to expand the range of potential participants and ensure competitive procurement conditions, we request confirmation of the following:1.      To allow the submission of the ISO 45001:2018 certificate as the correct and valid version of the standard.2.      To allow the submission of certificates issued in accordance with the National Standards of Ukraine, specifically DSTU ISO 9001:2015, DSTU ISO 14001:2015, and DSTU ISO 45001:2018.These Ukrainian national standards are identical (IDT) to the international versions in terms of content and requirements. Could you please confirm that providing such equivalent documents according to Ukrainian DSTU ISO standards is acceptable?_____ANSWER____Dear Bidder,Thank you for your observation. Please be advised that the Technical Specification will be amended to clarify the requirements and correct the technical typo. The revised clauses will read as follows:1.1 "The manufacturer of the offered Goods must be ISO 9001:2015 ,ISO 14001:2015 , ISO 45001:2019 (or their national DSTU equivalents) certified, and the Bidder shall provide a copies of these certificates for each manufacturer of the offered Goods."1.9.3 "Manufacturer's ISO 9001:2015 certificate (or national equivalent DSTU ISO 9001) - for each manufacturer of the offered Goods."1.9.4 "Manufacturer's ISO 14001:2015 certificate (or national equivalent DSTU ISO 14001) - for each manufacturer of the offered Goods."1.9.5 "Manufacturer's ISO 45001:2019 certificate (or national equivalent DSTU ISO 45001) - for each manufacturer of the offered Goods."Consequently, the submission of valid ISO 45001:2018 or DSTU ISO 45001:2019 certificates will fully comply with the updated requirements.Please monitor the platform for the official publication of the revised documentation.Best regards, Procurement Team 

New clarification added: Dear Sir/Madam, We are working on your tender. In order for us to submit an accurate proposal for your tender, our suppliers need to conduct a detailed analysis. Could you please kindly extend the tender deadline?We are waiting for your valuable reply.Kindly Regards._____ANSWER____Dear Bidder,Thank you for your question and for your interest in the tender.Please note that the deadline for submission of proposals is 08 April 2026 , while the tender was published on 23 March 2026. This provides a reasonable period for the preparation and submission of proposals.In light of the above, and considering the overall timeframe allocated for this tender, the deadline will not be extended.Should there be any changes, all participants will be duly informed.We appreciate your understanding and look forward to receiving your proposal.Best regards,Procurement Team

New clarification added: Dear Sir/Madam,We are working on your tender. Please kindly find the point thats needs to be clarified below.1. What are the required supply and return temperatures and the operating pressure for the system?We are waiting for your valuable reply.Kindly Regards._____ANSWER____Dear Bidder, Thank you for your question!Please refer to the Technical Specification section 2.1.4 "Service conditions and design parameters", which explicitly defines the following requirements for the bidding process:Application Class: 5 (according to EN ISO 15875-1).Operating Temperatures: Design operating temperature ≥ 60 °C, with a maximum (Tmax) of 90 °C and a malfunction (Tmal) of 100 °C.Pressure: The system must be suitable for a maximum design pressure (Pdes) of not less than 1.0 MPa (10 bar).Service Life: Guaranteed service life of 50 years must be calculated based on the cumulative temperature profile defined in EN ISO 15875-1 and EN 15632 under these specific conditions.The offered reinforced PE-Xa piping system, including fittings, must be fully certified and tested to operate reliably within these parameters.Best regards, Procurement Team