NZQA registered unit standard 8399 version 7 Page 1 of 3
Title Evaluate chrome tannage
Level 5 Credits 8
Purpose This unit standard is for experienced people wishing to develop their technical skills in leather manufacture.
People credited with this unit standard are able to: demonstrate knowledge of chrome tanning agents; evaluate the mechanism of chrome tannage; evaluate chrome tannage practices; and evaluate chrome tanned leather chemical and physical characteristics.
Classification Fellmongery and Leather Processing > Leather Processing Knowledge
Available grade Achieved
Explanatory notes
None.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of chrome tanning agents.
Evidence requirements
1.1 Method of manufacture of a chrome tanning agent is described in terms of reaction involved and production technique.
Range evidence is required of sulphur dioxide reduction or glucose reduction.
1.2 Chemistry of a basic chrome sulphate tanning agent is described in terms of characteristics relevant to tanning.
Range evidence is required of chrome complex form and one of – chromium oxide content, basicity, masking.
1.3 Problems associated with the use of chrome tanning agents on woolskins are described in terms of potential adverse effects on final product.
Primary Industry Training Organisation Ó New Zealand Qualifications Authority 2018 SSB Code 101558 NZQA registered unit standard 8399 version 7 Page 2 of 3
Outcome 2
Evaluate the mechanism of chrome tannage.
Evidence requirements
2.1 Mechanism of chrome tannage is evaluated in terms of reagent penetration and subsequent fixation to skin.
Range evidence is required of chrome complex interaction with collagen.
Outcome 3
Evaluate chrome tannage practices.
Evidence requirements
3.1 Process methods for chrome tannage are evaluated in terms of procedure and key principles.
Range evidence is required of two of the following – pickle tannage with soda ash basification, self basifying tannage, masked tannage, no pickle tannage, long float.
3.2 Tanning vessels are evaluated in terms of suitability for hides and skins, or woolskins.
3.3 Practical controls used in chrome tanning are evaluated in relation to chrome penetration and fixation.
Range evidence is required of five of the following – delime penetration, pickle penetration, float length, pH, mechanical action, time, basification rate, temperature, shrinkage temperature.
Outcome 4
Evaluate chrome tanned leather chemical and physical characteristics.
Evidence requirements
4.1 Chrome tanned leather is evaluated in terms of chemical and physical characteristics.
Range evidence is required of cationic charge, thermal stability, plus one of the following – shape retention, substance, dyeability, wettability, durability.
Planned review date 31 December 2017
Status information and last date for assessment for superseded versions
Primary Industry Training Organisation Ó New Zealand Qualifications Authority 2018 SSB Code 101558 NZQA registered unit standard 8399 version 7 Page 3 of 3
Process Version Date Last Date for Assessment Registration 1 24 September 1996 31 December 2014 Revision 2 16 September 1997 31 December 2014 Review 3 27 April 2000 31 December 2014 Revision 4 20 February 2002 31 December 2014 Revision 5 14 October 2004 31 December 2104 Review 6 14 December 2007 31 December 2015 Review 7 21 February 2013 N/A
Consent and Moderation Requirements (CMR) reference 0033 This CMR can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Please note Providers must be granted consent to assess against standards (accredited) by NZQA, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment.
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Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards.
Requirements for consent to assess and an outline of the moderation system that applies to this standard are outlined in the Consent and Moderation Requirements (CMR). The CMR also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact the Primary Industry Training Organisation [email protected] if you wish to suggest changes to the content of this unit standard.
Primary Industry Training Organisation Ó New Zealand Qualifications Authority 2018 SSB Code 101558