EN 4171:2011

Aerospace series - Paints and varnishes - Test method for determination of phosphoric acid index

This European Standard specifies a method for the titration and determination of the phosphoric acid content of an hydroalcoholic solution for aerospace applications.
This test method is relevant for the determination of total acidity and phosphoric acid content in a reactive thinner of a wash primer or in metal cleaners.

Luft- und Raumfahrt - Beschichtungsstoffe - Prüfverfahren zur Bestimmung des Phosphorsäure-Index

Diese Europäische Norm legt ein Verfahren zur Titration und Bestimmung des Phosphorsäuregehaltes einer wässrig-alkoholischen Lösung für Anwendungen in der Luft- und Raumfahrt fest. Dieses Prüfverfahren ist für die Bestimmung der Gesamtsäurezahl und des Phosphorsäuregehaltes in einem reaktiven Verdünner eines Washprimers (Haftgrundmittels) oder in Metallreinigern von Bedeutung.

Série aérospatiale - Peintures et vernis - Méthode d'essai pour la détermination de l'indice d'acide phosphorique

Aeronavtika - Barve in laki - Preskusna metoda za ugotavljanje indeksa fosforne kisline

Ta evropski standard določa metodo za titracijo in ugotavljanje vsebnosti fosforne kisline v vodno-alkoholni raztopini za uporabo v aeronavtiki.
Preskusna metoda je primerna za ugotavljanje skupne kislosti in vsebnosti fosforne kisline v reaktivnem razredčevalcu čistilnega sredstva za pripravo površine ali v čistilih za kovino.

General Information

• Status: Published
• Publication Date: 13-Dec-2011
• Withdrawal Date: 29-Jun-2012
• ICS: 49.040 - Coatings and related processes used in aerospace industry
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 5 - Non-Metallic
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 01-Jun-2017
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 4171:2012 - Aerospace series - Paints and varnishes - Test method for determination of phosphoric acid index

Overview

EN 4171:2011 is a CEN European test standard for the aerospace sector titled Aerospace series - Paints and varnishes - Test method for determination of phosphoric acid index. It specifies a laboratory titration method to determine the phosphoric acid content and total acidity of hydro‑alcoholic solutions used in aerospace coatings - notably reactive thinners for wash primers and aqueous metal cleaners.

Key topics and requirements

• Scope: Measurement of phosphoric acid in hydroalcoholic solutions relevant to etch/activator components of wash primers and metal cleaners.
• Principle: Ionize phosphoric acid and titrate with standardized sodium or potassium hydroxide; identify successive pH jumps to locate end points for total acidity and phosphoric acid.
• Sampling & preparation: Test specimens are taken directly from the original container and prepared per referenced ISO methods.
• Apparatus & reagents:
  • Conical (Erlenmeyer) flasks, burette (50–100 ml), pipette (10 ml)
  • PTFE magnetic stirrer, pH electrode or automatic titrator, SCE reference electrode
  • Buffered solutions (pH 4.5 and 6.2), indicator solutions (helianthine, phenolphthalein)
  • 1 N NaOH or KOH titrant (calibrated)
  • Analytical grade chemicals and high‑purity water (EN ISO 3696)
• Procedure (high level):
  • Dilute a defined aliquot (typically 10 ml) of specimen to a fixed volume with distilled water.
  • Titrate with standardized base, recording pH (potentiometric) or observing colour change for manual end points.
  • Determine volumes of alkali at the first and second end points (V1 and V2). Use the difference (V2 − V1) to calculate phosphoric acid content to avoid interference from other strong acids.
• Results & reporting: Calculate acid normality and phosphoric acid content using the titrant normality, specimen volume and measured volumes. Report standard reference, sample ID, batch, titrant normality, measured values and method used.

Applications & users

• Quality control laboratories in aerospace coatings and surface treatment suppliers
• Paint and primer formulators validating reactive thinners and wash primer activators
• Manufacturers of metal cleaners used for aluminium surface preparation
• Certification bodies and auditors assessing conformity with aerospace material specifications

Related standards

• EN ISO 1513 - Examination and preparation of test samples
• EN ISO 3696 - Water for analytical laboratory use
• EN ISO 15528 - Sampling of paints and raw materials

EN 4171 is essential for accurate measurement of phosphoric acid index in aerospace coating processes, helping ensure consistent etch/activation performance, corrosion control and regulatory compliance.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aeronavtika - Barve in laki - Preskusna metoda za ugotavljanje indeksa fosforne kislineLuft- und Raumfahrt - Anstrichstoffe - Prüfverfahren zur Bestimmung des Phosphorsäure-IndexSérie aérospatiale - Peintures et vernis - Méthode d'essai pour la détermination de l'indice d'acide phosphoriqueAerospace series - Paints and varnishes - Test method for determination of phosphoric acid index49.040Prevleke in z njimi povezani postopki, ki se uporabljajo v letalski in vesoljski industrijiCoatings and related processes used in aerospace industryICS:Ta slovenski standard je istoveten z:EN 4171:2011SIST EN 4171:2012en01-februar-2012SIST EN 4171:2012SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 4171
December 2011 ICS 49.040 English Version
Aerospace series - Paints and varnishes - Test method for determination of phosphoric acid index
Série aérospatiale - Peintures et vernis - Méthode d'essai pour la détermination de l'indice d'acide phosphorique
Luft- und Raumfahrt - Beschichtungsstoffe - Prüfverfahren zur Bestimmung des Phosphorsäure-Index This European Standard was approved by CEN on 27 August 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 4171:2011: ESIST EN 4171:2012
...