NZQA registered unit standard
Title
Evaluate vegetable tannage
Level
5
27898 version 1
Page 1 of 3
Credits
Purpose
8
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 vegetable tanning agents; evaluate the
mechanism of vegetable tannage; evaluate vegetable tanning
practice; and evaluate vegetable tanned leather characteristics.
Classification
Fellmongery and Leather Processing > Leather Processing
Knowledge
Available grade
Achieved
Explanatory notes
None.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of vegetable tanning agents.
Evidence requirements
1.1
Vegetable tanning agents are explained in terms of their origins and leather
making properties.
Range
evidence is required of mimosa plus two others, which may
include but are not limited to – quebracho, chestnut, myrabolams,
valonia, sumach.
1.2
The key differences between condensed and hydrolysable tannins are outlined
in terms of their tanning properties.
1.3
The suitability of different vegetable tanning agents for specific leather types is
explained.
Range
evidence is required of two of the following – sole leather, insole
material, upholstery, saddlery, case leather, belt, industrial leather.
Primary Industry Training Organisation
SSB Code 101558
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
27898 version 1
Page 2 of 3
Outcome 2
Evaluate the mechanism of vegetable tannage.
Evidence requirements
2.1
Mechanism of vegetable tannage is evaluated in terms of penetration and
subsequent fixation to skin.
Outcome 3
Evaluate vegetable tanning practice.
Evidence requirements
3.1
Process method for vegetable tannage is evaluated in terms of procedure and
key principles.
Range
3.2
evidence is required of one of the following – counter current pit
system, combined pit/drum method, rapid drum method.
Tannage control parameters are evaluated in terms of vegetable tanning
practice.
Range
evidence is required of three of the following – acidity, salt
balance, tans to non-tans ratio, tan strength, temperature, time,
mechanical action.
Outcome 4
Evaluate vegetable tanned leather characteristics.
Evidence requirements
4.1
Vegetable tanned leather is evaluated in terms of chemical and physical
characteristics.
Range
evidence is required of four of the following – anionic, thermal
stability, shape retention, substance, dyeability, water resistance,
strength, stretch, lightfastness, abrasion resistance.
Replacement information
Planned review date
This unit standard replaced unit standard 8400.
31 December 2017
Primary Industry Training Organisation
SSB Code 101558
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
27898 version 1
Page 3 of 3
Status information and last date for assessment for superseded versions
Process
Version Date
Last Date for Assessment
Registration
1
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.
Industry Training Organisations must be granted consent to assess against standards by
NZQA before they can register credits from assessment against unit standards.
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 standards@primaryito.ac.nz if
you wish to suggest changes to the content of this unit standard.
Primary Industry Training Organisation
SSB Code 101558
 New Zealand Qualifications Authority 2016