SIST EN 1991-4:2026/oprA1:2026

• Abstract:

  1.1 Scope of EN 1991-4; (1) This document provides rules for calculating actions for the structural design of silos and tanks.; NOTE 1 Silos are used for the storage of particulate solids. Tanks are used for the storage of liquids.; NOTE 2 For limitations on rules for silos given in this document, see 1.3.; NOTE 3 For limitations on rules for tanks given in this document, see 1.4.; (2) This document includes some provisions for actions on silo and tank structures that are not only associated with the stored particulate solids or liquids (e.g. the effects of thermal differentials) but substantially affected by them.; NOTE Liquid loads on tanks are very precisely defined. Many loads on silos are not known with great precision. This document provides guidance for many practical situations for which very limited certain knowledge is available, and the information is derived from the limited experimental and analytical information available, coupled with conclusions drawn from failure investigations. The information is not based on a sound statistical treatment of experimental data.; (3) This document is intended for use with concrete, steel, aluminium, timber and FRP storage structures.; NOTE FRP is the standard acronym for fibre reinforced polymer materials.; (4) This document is also applicable for the structural assessment of existing silos and tanks, unless otherwise specified by the relevant authority or, if not specified, agreed between the relevant parties for the specific project.; NOTE 1 Changes in filling or discharge arrangements, changes in the wall friction of inner surfaces, or in the use of the silo, including storage of different particulate solids, can be reasons for assessing existing silos.; NOTE 2 Differentiation of the liquid stored can be a reason for assessing existing tanks.; 1.2 Assumptions; (1) The assumptions of EN 1990-1 apply.; (2) This document is intended to be used in conjunction with EN 1990 1, with the other parts of EN 1991, EN 1992, EN 1993, EN 1995, EN 1997, EN 1998 and EN 1999 where relevant to the design of silos and tanks.; 1.3 Limitations on silos; 1.3.1 Geometrical limitations; (1) The following geometrical limitations apply to the design rules for silos and silo batteries (see 3.2.59 and 3.2.60) covered by this document:; - the silo planform cross-section shapes are limited to those shown in Figure 1.1c.; NOTE 1 Further information concerning planform cross-section geometries is given in Clause 7.; NOTE 2 For the determination of the effective diameter dc of the silo see Figure 1.1c;; - the following dimensional limitations on the aspect ratio for free-standing single cell silos hc/dc, the overall height hb and the effective diameter dc apply (see Figure 1.1):; hc/dc < 10 (1.1); hb < 100 m (1.2); dc < 60 m (1.3); NOTE 3 See Figure 1.1 for hc, dc and hb.; - the structural transition lies in a single horizontal plane (see Figure 1.1a).; [Figure 1.1 - Silo forms showing dimensions and pressure notation]; (2) Only hoppers that are conical (i.e. axisymmetric), rectangular pyramidal with a/b ≤ 1,5, wedge-shaped (i.e. with two vertical end walls on opposite sides) or oblique are covered by this document. Other hopper shapes and hoppers with internal structures require special considerations.; (3) Silos with an oblique conical hopper used to achieve an eccentric outlet are covered by this document.; (4) Silos with an oblique hopper are covered, but generally silos with a systematically non-symmetric geometry are not specifically covered by this document. These situations include a chisel hopper (i.e. a wedge hopper beneath a circular cylinder) and hoppers with an elongated outlet other than wedge shaped.; 1.3.2 Limitations on the stored particulate solids; (1) The following limitations on the stored particulate solids apply to the design rules for silos contained in this document:; ...

• Status: Not Published
• Public Enquiry End Date: 27-Sep-2026
• ICS: 23.020.10 - Stationary containers and tanks
• ICS: 91.040.01 - Buildings in general
• Technical Committee: KON - Structures
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 29-Jul-2026
• Due Date: 16-Dec-2026
• Ref Project: EN 1991-4:2026/prA1 - Eurocode 1 - Actions on structures - Part 4: Silos and tanks

• Amends: kSIST FprEN 1991-4:2025 - Eurocode 1 - Actions on structures - Part 4: Silos and tanks
• Effective Date: 29-Apr-2026

Overview

SIST EN 1991-4:2026/oprA1:2026, part of the second generation Eurocode suite developed by CEN/TC 250, sets out comprehensive rules for calculating structural actions on silos and tanks. This European Standard is essential for engineers and designers engaged in the storage infrastructure of particulate solids (silos) and liquids (tanks). It ensures uniformity and safety in the design and assessment of new and existing storage structures across Europe. The standard is applicable to a range of construction materials, including concrete, steel, aluminium, timber, and fibre reinforced polymer (FRP).

Key Topics

• Scope and Applicability
  SIST EN 1991-4:2026/oprA1:2026 provides rules for:

  • Calculating actions for structural design of both silos and tanks.
  • Addressing not only loads from stored materials but also other relevant actions, such as those arising from thermal effects.
  • Both new construction and structural assessment of existing silos and tanks.

• Material and Geometrical Limitations
  The standard covers structures made of various materials and provides:

  • Specific dimensional and geometrical requirements (e.g., maximum aspect ratios, heights, effective diameters).
  • Planform cross-section shapes and hopper types (conical, rectangular pyramidal, wedge-shaped, oblique).
  • Limitations on stored particulate solids, excluding certain silo shapes and unusual installations from the standard scope.

• Design Considerations

  • Addresses uncertainties inherent in silo loads compared to more precise tank loads.
  • Notes on practical derivation from experimental, analytical, and failure data due to limited statistical information.
  • Provides for national adaptation via National Annexes to address unique regulatory safety requirements in member states.

• Updates in Draft Amendment (prA1)

  • Editorial corrections and clarification regarding functional design and exceptional load cases.
  • Exclusion of functional flow design and specific dynamic actions (like silo quaking) from the scope.
  • Enhanced guidance on the use of insulation and granular materials in tank structures.

Applications

SIST EN 1991-4:2026/oprA1:2026 is widely used in the engineering and construction sectors for:

• Structural Design:
  Informing the safe and efficient design of silo and tank structures, ensuring they can safely withstand all relevant actions from stored materials and environmental effects.

• Assessment of Existing Structures:
  Serving as a reference for evaluating the continued suitability of silos and tanks, especially following changes in usage, discharge arrangements, or stored materials.

• Material Selection:
  Supporting design decisions involving concrete, steel, aluminium, timber, and FRP, in line with the Eurocode’s integrated approach with other relevant standards.

• Regulatory Compliance:
  Helping companies demonstrate compliance with European and national building regulations as it is widely harmonized across CEN member countries.

• Project Specification:
  Used by project planners, specifiers, and contractors to ensure consistent, evidence-based requirements in tenders and project documentation.

Related Standards

To ensure comprehensive structural safety and compatibility, SIST EN 1991-4:2026/oprA1:2026 should be used in conjunction with these standards:

• EN 1990: Basis of structural design
• EN 1991 parts 1-3, 1-6: Actions on structures (covers general, wind, snow, temperature, and crane actions)
• EN 1992: Design of concrete structures
• EN 1993: Design of steel structures
• EN 1995: Design of timber structures
• EN 1997: Geotechnical design
• EN 1998: Design of structures for earthquake resistance
• EN 1999: Design of aluminium structures

By referencing SIST EN 1991-4:2026/oprA1:2026 along with related Eurocodes, stakeholders ensure comprehensive and harmonized approaches to the design, construction, and assessment of silos and tanks in Europe’s built environment.

Keywords: Eurocode 1, EN 1991-4, actions on structures, silos, tanks, CEN, structural design, storage structures, particulate solids, liquid storage, European Standard, structural assessment, compliance, silo limitations, tank limitations.

SLOVENSKI STANDARD
01-september-2026
Evrokod 1 - Vplivi na konstrukcije - 4. del: Silosi in rezervoarji
Eurocode 1 - Actions on structures - Part 4: Silos and tanks
Eurocode 1 - Einwirkungen auf Tragwerke - Teil 4: Einwirkungen auf Silos und
Flüssigkeitsbehälter
Eurocode 1 - Actions sur les structures - Partie 4 : Actions sur les silos et les réservoirs
Ta slovenski standard je istoveten z: EN 1991-4:2026/prA1
ICS:
23.020.10 Nepremične posode in Stationary containers and
rezervoarji tanks
91.040.01 Stavbe na splošno Buildings in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
EN 1991-4:2026
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA1
July 2026
ICS
English Version
Eurocode 1 - Actions on structures - Part 4: Silos and tanks
Eurocode 1 - Actions sur les structures - Partie 4 : Eurocode 1 - Einwirkungen auf Tragwerke - Teil 4:
Actions sur les silos et les réservoirs Einwirkungen auf Silos und Flüssigkeitsbehälter
This draft amendment is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 250.

This draft amendment A1, if approved, will modify the European Standard EN 1991-4:2026. If this draft becomes an amendment,
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of
this amendment into the relevant national standard without any alteration.

This draft amendment was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1991-4:2026/prA1:2026 E
worldwide for CEN national Members.

EN 1991-1-1:2026/prA1:2026 (E)
Contents Page
European foreword .
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